GIFT  OF 
Thomas    H.    Me an 3 


._  r,la  1.  n   1 1  h  i'>n  -py    / .  p- -n  1  p.  ^    Q  e  tS t 


••5fHt. 


P 


CHYMISTRY. 


ATVLII^D   TO 


AGRICULTURE. 


Br  JOHN  ANTONY  CHAPTAL, 

COUNT    OF    CHAIfTILOUP,    PEER    OF    FBANCE,    MEMBER   OF    THE    INSTITUTE,    &C. 


TRANSLATED  FROM  THE  SECOND  FRENCH  EDITION. 


Omnium  rerum,  ex  quibus  aliquid  acquiritur,  nihil  est  agriculture  melius,  nihil 
uberius,  nihil  dulcius,  nihil  libero  homine  dignius. — Cicero. 

Good  husbands  will  find  the  means,  by  good  husbandry,  to  improve  their  lands  ; 
but  it  will  not  be  amiss  that  they  be  put  in  mind  thereof,  and  encouraged 
in  their  industries. — Lord  Bacon. 


BOSTON: 
BILLIARD,    GRAY,    AND    CO. 

1839. 


:iM2^:'^.^-x'     7-/.  /^t^*-.^ 


Entered  according  to  act  of  Confess,  in  the  year  one  thousand 
eight  hundred  and  thirty-five,  by  Hilliard,  Gray,  and  Co.,  in  the 
Clerk's  office  of  the  District  Court  of  the  District  of  Massachusetts. 


STEREOTYPED  AT  THE 
BOSTON  TYPE  AND  STEREOTYPE  FOUNDRY. 


ADVERTISEMENT 


In  offering  to  the  public  the  following  treatise  the 
publishers  believe  that  they  shall  render  an  acceptable 
service  to  the  agricultural  interest,  the  most  important 
interest,  of  the  United  States. 

The  author,  one  of  the  most  eminent  chymists  of  the 
age,  was  at  the  same  time  a  practical  agriculturist,  own- 
ing large  estates,  which  were  for  a  long  time  cultivated 
under  his  personal  direction.  "  In  order,"  says  he,  '*  to 
make  a  useful  application  of  the  sciences  to  agriculture, 
it  must  be  profoundly  studied,  not  only  in  the  closet,  but 
abroad  in  the  fields."  By  pursuing  this  method  he  was 
able  to  describe  processes,  and  set  down  the  course  and 
the  results  of  his  large  experience,  with  a  fulness  and 
clearness,  that  make  them  immediately  available  to  the 
practical  farmer.  "  In  my  explanations,"  he  remarks, 
**  I  may  sometimes  have  fallen  into  error,  but  I  do  not 
believe  that  I  have  misstated  a  single  fact." 

The  only  work  of  note  in  the  English  language  on  the 
subject  of  Agricultural  Chymistry  is  that  of  Davy,  which 
was  published  in  the  year  1813.  It  consists  of  eight 
lectures  delivered  annually  for  ten  years  before  the 
Board  of  Agriculture.  In  his  preface  he  observes,  that 
the  rapid  advance  of  chymical  science  obliged  him  to 
vary  them  each  year  they  were  delivered,  and  to  alter 
them  still  further  when  preparing  them  for  the  press. 

Ten  years  afterwards,  in  1823,  appeared  the  first  edi- 
tion of  the  present  work,  in  which  the  author  says,  **  The 
celebrated  Davy  has  already  published  an  Agricultural 

678991 


IV  ADVERTISEMENT. 

Chymistry,  and  I  have  derived  from  it  important  princi- 
ples. Others  will  do  better  than  we  have  done."  But 
no  one  came  forward  to  verify  this  prediction,  and,  in 
1829,  Chaptal  published  a  second  edition,  increased  by 
several  new  chapters  and  a  copious  Index.  To  this,  the 
author's  last  edition,  the  present  translation  is  con- 
formed.* 

Although  the  work  was  more  especially  intended  for 
France,  the  larger  portion  of  it  is  applicable  to  all  coun- 
tries ;  and  those  chapters,  which  at  first  view  seem  to 
have  only  a  local  interest,  abound  in  hints  which  may 
anywhere  be  turned  to  account. 

And  not  only  is  the  husbandman  taught  how  to  pro- 
duce, but  the  housekeeper  also  how  to  preserve,  and 
enjoy  in  perfection,  the  various  products  of  agricultural 
labor. 

The  opinions  of  Chaptal  on  pohtical  science  were 
in  harmony  with  the  institutions  of  the  United  States. 
He  was  an  advocate  for  breaking  up  the  large  domains  of 
France  into  small  farms,  which  should  gradually  be  pur- 
chased by  those  who  succeeded  in  cultivating  them. 
He  sought  to  raise  the  peasantry  of  his  country  from  their 
ignorance  and  degradation  to  the  condition  of  '*  indepen- 
dent farmers,"  in  the  American  sense  of  the  term ;  to 
make  them  feel  the  intrinsic  dignity  of  their  employment 
while  practising  the  most  important  of  all  arts,  that  which 
lies  at  the  very  foundation  of  civil  society.  To  this  end 
he  wrote  the  present  work,  which  sheds  all  the  light  of 
modern  science  upon  the  humblest  details  of  rural  labor ; 
and,  while  it  increases  the  productive  skill  of  those  who 
are  engaged  in  practical  husbandry,  at  the  same  time 
"  advances  them  in  the  dignity  of  thinking  beings." 

*  Chaptal  died  on  the  29th  of  July,  1833,  in  his  76th  year. 


CONTENTS. 


INTRODUCTION    .        .  ....  xi 

CHAPTER    I. 

General  Views    of   the  Atmosphere,  considered  in 
ITS  Effects  upon  Vegetation  ....      1 

Article  1.    Of  the  Ponderable  Fluids  contained  in  the 

Atmosphere 9 

2.     Of  the  Imponderable    Fluids    contained  in 

the  Atmosphere 1 

CHAPTER   II. 

Of  the  Nature   of  Earths,  and  their  Action  upon 
Vegetation 14 

Article  1.    Of  Mould 15 

2.  Of  the  Nature  of  Soils         ....  18 

3.  Of  the  Formation  of  Arable  Lands       .        .  19 

4.  Of  the  Composition  of  Arable  Lands   .        .  24 

5.  Of  the  Properties  of  the  different  Earths      .  30 

6.  Of  the  Properties    of  Mixed    Earths,   and 

the  Methods  of  rendering  them  capable 

of  a  good  Cultivation       .        .        .        .38 

7.  Of  the  Analysis  of  Arable  Soils         .        .    44 

CHAPTER   III. 

Of  the  Nature  and  Action  of  Manures     .       .        .49 

Article  1.    Of  Nutritive  Manures  ....    50 

2.    Of  Stimulating  Manures       .        .        .        .    d6 


▼I  CONTENTS. 

CHAPTER   IV. 
Op  Germination 77 

CHAPTER   V. 
Of  the  Nourishment  of  Plants 80 

Article  1.    The  Influence  of  Carbonic  Acid  Upon  Nu- 
trition       80 

2.  The  Influence  of  Oxygen  Gas  upon  Nutri- 

tion           82 

3.  The  Influence  of  Air  upon  Fruits       .        .  85 

4.  The  Influence  of  Water  upon  Nutrition     .  89 

5.  Of  the  Efiects  of  the  Nourishment  of  Plants 

upon  the  Soil 92 

(J.    Summary  of  the  Changes  produced  in  Plants 

by  Nourishment 99 

CHAPTER   VI. 
Improtement  of  the  Soil 106 

CHAPTER  VII. 
Of  the  Succession  of  Crops 120 

Principle  1.    All  plants  exhaust  the  soil  .        .        .    121 

2.  All  plants  do  not  exhaust  the  soil  equally    .    121 

3.  Plants  of  difierent  kinds  do  not  exhaust 

the  soil  in  the  same  manner    .        .        .     123 

4.  All  plants  do  not  restore  to  the  soil  either 

the  same  quantity  or  the  same  quality  of 
manure 124 

5.  All  plants  do  not  foul  the  soil  equally         .    124 

CHAPTER   VIII. 
^iBTf  OF  THE  Products  of  Peknch  Agbicultuee  131 


CONTENTS-  Vlfc 


CHAPTER   IX. 


Of  the  Nature  and  Uses  of  the  Products  of  Vege- 
tation            132 

Article  1.    Gum  and  Mucilage 135 

2.  Starch  or  Fecula 136 

3.  Sugar 140. 

4.  Wax  .        ., 141 

5.  OUs 143 

6.  Resin 147 

7.  Vegetable  Fibre 149 

8.  Gluten  and  Albumen 154 

9.  Tannin 157 

10.  The  Vegetable  Acids         ....  159 

11.  The  Fixed  Alkalies 168 

CHAPTER   X. 

Oj^   THE    Preservation    of    Animal  and   Vegetable 

Substances 182 

Article  1,    On  the  Preservation  of  the  Fruits  of  the 

Earth  by  Drying J83 

2.  On  the   Preservation  of  the  Fruits  of  the 

Earth  by  Secluding  them  from  the  Ac- 
tion of  Air,  Water,  and  Heat         .        .  ]88 

3.  On  the  Preservation  of  certain  Articles  of 

Food  by  means  of  Salt  and  Spirituous 

Liquors 200 

CHAPTER   XL 

On  Milk  and  its  Products 207 

Article  1.    Of  Cream 209 

2.  Of  Butter 210 

3,  Of  Caseous,  or  Cheesy,  Matter  .        .       .  214 


Vin  CONTENTS. 

CHAPTER  XII. 

Comparison  between  an  Agricultural  and  a  Manu- 
facturing Nation     .......    221 

CHAPTER   Xni. 
On  Large  and  Small  Estates 224 

CHAPTER   XIV. 

The  Encouragement   which   ought   to    be   given  bt 

THE  Government  to  French  Agriculture  .        .    232 

CHAPTER   XV. 
Ov  Fermentation 238 

CHAPTER   XVI. 
On  Distillation 252 

CHAPTER  XVII. 

On  the  Means  of  preparing  Wholesome  Drinks  for 

THE  Use  of  Country  People  .        .        .        .    271 

CHAPTER   XVIII. 

Of  Farm  Buildings,  both  for  Men  and  Animals,  and 

THE  Means  op  Making  them  Healthy  .        .        .    283 

CHAPTER  XIX. 
On  Washing,  Bleaching,  &c 289 

CHAPTER   XX. 

On  the  Cultivation  of  Woad,  and  the  Extraction 

of  Indigo  from  it 294 


CONTENTS.  yC 

Article  1.    On  the  Cultivation  of  Woad       .        .        .  205 

2.  Preparation  of  Woad  Cakes        .        .        .  297 

3.  The  E^^traction  of  Indigo  fi:om  Woad         .  302 

CHAPTER   XXI. 

On  the  Cultivation  op  the  Beet  Root,  and  the  Ex- 
traction OF  Sugar  from  it 315 

SECTION  I.    On  the  Cultivation  of  the  Beet  Root  .        .  315 

Article  1.    On  the  Choice  of  Seed       ....  316 

2.  On  the  Choice  of  Soil  .        .        .        .317 

3.  On  the  Preparation  of  the  Soil    .        .        .  3L8 

4.  On  the  Manner  of  Sowing  Beet  Seed         .  319 

5.  On  the    Care    required    by  Beets  during 

their  Vegetation 320 

6.  On  the  Gathering  of  Beet  Roots         .        .  321 

7.  On  the  best  Method  of  Keeping  Beet  Roots  322 

SECTION  II.    On  the  Extraction  of  Sugar  from  Beets  324 

Article  1.    On  the  Preparation  of  the  Roots        .        .  324 

2.  On  the  Method  of  Rasping  the  Beet  Roots  325 

3.  On  the  Extraction  of  the  Juice    .        .        .  325 

4.  On  the  Purification  of  the  Juice          .        .  327 

5.  On  the  Concentration  or  Evaporation  of  the 

Purified  Juice 330 

6.  On  Boiling  the  Sirup  .        .        .        .331 

7.  On    Boiling  the    Molasses   and  Leaching 

Sirups 336 

SECTION  III.    On  the  Refining  of  Sugar  obtained  from 

Beet  Roots .  337 

Article  1.    On  Clarification 338 

2.    On  Whitening  Sugar          ....  339 

SECTION  IV.    On  tiie  Distillation  of  Molasses        .        .  345 

SECTION  V.    On  the  Products  of  a  Sugar  Manufactory  348 

A* 


X  CONTENTS. 

Article  1.    Of  the  Product  in  Sugar    ....  348 

2.  Of  the  Secondary  Products         ...  349 

3.  On  the  Value  of  the  Products    .        .        .  349 

SECTION  VI.    On  the  Expense  of  a  Sugar  Manufactory  351 

{SECTION  VII.    General  Ck)nsiderations  .  .  354 


INTRODUCTION 


Without  agriculture,  men  would  live  wandering  and 
unsettled  lives,  disputing  with  each  other  for  the  posses- 
sion of  such  animals  as  they  could  make  their  prey, 
and  for  the  spontaneous  fruits  of  the  earth.  They  would 
have  no  bond  of  society,  nor  country. 

By  multiplying  the  resources  for  food,  agriculture  has 
permitted  men  to  unite  themselves  into  communities  for 
mutual  assistance.  Whilst  some  cultivate  the  land,  to  in- 
crease its  productions,  others  apply  themselves  assiduously 
to  furnishing  society  with  the  necessary  implements  of  in- 
dustry. It  is  thus  that,  by  reciprocal  intercourse  and  ex- 
changes, commerce  has  been  established,  and  civilization 
extended. 

If  living  in  cities,  and  leading  the  sedentary  life  required 
by  the  practice  of  many  of  the  arts,  have  softened  and 
enervated  a  portion  of  the  human  species,  agriculture  has 
preserved  the  inhabitants  of  the  country  in  a  state  of 
health,  strength,  and  good  morals.  Nor  is  it  one  of  the 
least  blessings  which  it  bestows  upon  society,  that  it 
thus  continually  repairs  that  portion  of  it  which  would 
otherwise  become  degenerate. 


Xll  INTRODUCTION. 

Amongst  all  nations,  agriculture  is  the  purest  source 
of  public  prosperity.  Situated  under  different  climates, 
their  productions  and  modes  of  cultivation  are  extremely 
diversified.  But  commerce  scatters  the  productions  of 
the  various  soils ;  and  thus  each  nation  is  able  to  enjoy 
the  fruits  peculiar  to  the  several  portions  of  the  earth. 
These  exchanges  haye  connected  nations  together,  by 
rendering  them  dependent  on  each  other ;  and  the  advan- 
tages arising  from  intelligence  and  industry  have  been 
made  to  spread  through  all. 

The  agriculturist,  then,  holds  the  first  rank  amongst 
men.  By  what  fatality  has  his  condition,  in  France, 
been  always  miserably  servile  and  degraded  ?  Those, 
even,  whom  he  has  toiled  to  support  in  luxury  and  idle- 
ness, have  often  compelled  him  to  envy  the  condition  of 
the  animals  which  assist  him  in  his  labors.  The  statute 
work,  the  tithes,  and  the  other  exactions  of  feudal  power, 
have  left  him,  for  his  subsistence,  only  the  most  wretched 
productions  of  his  fields.  He  has  watered  the  land  with  ' 
the  sweat  of  his  brow,  but  the  fruits  which  it  brought 
forth  were  for  the  enjoyment  of  others.  In  this  state  of 
misery  and  oppression,  the  cultivator  of  the  soil  followed 
blindly  the  track  which  was  marked  out  for  him.  Without 
emulation,  without  knowledge,  and  nearly  without  inter- 
est, the  thought  of  improvement  scarcely  presented  itself 
to  his  mind. 

It  was  not  till  the  moment,  when,  by  a  wise  return  to 
the  true  principles  of  justice,  the  right  of  property  was 
respected  and  received  protection, — when  taxes  were 
proportionably  levied,  and  privileges  abolished, — that  the 
fjirmer  recognised  his  strength,  and  felt  himself  rising 
into  the  true  importance  and  dignity  of  his  state.     Then, 


INTRODUCTION.  XJU 

intelligence  was  extended  to  the  business  of  the  fields ; 
the  means  of  ameliorating  the  soil,  and  improving  its  pro- 
ductions, were  established  and  increased ;  and  private  in- 
terest was  for  ever  united  to  the  public  good.  At  that 
period,  agriculture  took  a  new  impulse ;  and  since  then, 
its  progress  has  been  rapid.  The  nature  of  soils  has 
been  better  known ;  the  cultivation  of  artificial  meadows 
has  been  extended ;  and  a  rotation  of  crops  has  been 
established  upon  principles  recognised  in  all  those  coun- 
tries, where  agriculture  has  made  the  most  progress. 
The  number  of  domestic  animals  has  also  progressively- 
increased,  and,  with  them,  the  manures  and  the  labors 
which  form  the  basis  of  agricultural  prosperity. 

It  remains  to  us,  at  this  day,  to  improve  agriculture  by 
the  application  of  physical  science.  All  the  phenomena 
which  it  presents,  are  the  consequences  necessarily  re- 
sulting from  those  eternal  laws  by  which  matter  is  gov- 
erned ;  and  all  the  operations  which  the  agriculturist  per- 
forms, serve  only  to  develope  or  modify  these  laws.  It 
is,  then,  to  the  acquisition  of  a  knowledge  of  these  laws,  in 
order  to  calculate  their  effects  and  modify  their  action, 
that  we  ought  to  direct  all  our  researches. 

Can  any  study  present  to  the  agriculturist  more  attrac- 
tions, than  that,  which  has  for  its  object  the  explanation 
of  those  effects,  which  every  day  captivate  his  senses 
and  astonish  his  reason  ?  Without  doubt,  observation 
has  made  him  acquainted  with  the  uniform  march 
of  nature.  In  all  her  operations,  he  can  judge  of  the 
modifications  effected  in  her  productions  by  the  state 
of  the  atmosphere,  the  variation  of  climate,  and  the 
nature  of  the  soil.  Even  this  practical  knowledge  en- 
ables   him  to   direct   many  of  the   labors  of  the   field. 


XIV  INTRODUCTION. 

But,  if  he  be  permitted  to  ascend  from  the  effects  to 
their  causes;  if  we  can  determine,  and  demonstrate  to 
him,  the  action  which  is  exercised  upon  vegetation  by 
the  air,  water,  heat,  and  hght,  the  sun,  various  kinds 
of  manure,  &c.  &c.,  and  assign  to  each  of  these  agents 
the  part  which  it  performs  in  these  grand  phenomena, 
how  much  will  he  be  moved  !  Even  whilst  an  igno- 
rant witness  of  these  wonders,  he  is  lost  in  admiration 
of  them :  but,  more  enlightened,  he  will  feel  this  sen- 
timent constantly  increasing,  as  he  rises  to  the  causes 
which  produce  them. 

Convinced  that  we  must  look,  for  farther  improve- 
ments in  agriculture,  to  the  application  of  the  physical 
sciences,  I  think  it  proper  here  to  establish  some  general 
principles,  the  more  complete  developement  of  which 
will  be  found  in  this  work. 

The  laws  of  nature  are  eternal  and  unchangeable. 
The  natural  state  of  bodies,  their  respective  situations, 
the  changes  which  they  undergo,  the  phenomena  of 
decomposition  and  of  composition,  which  animate  the 
whole  surface  of  the  globe,  are  the  results  of  these  laws. 

We  see,  everywhere,  that  matter  is  governed  by  two 
general  laws  ;  by  the  power  of  which  all  bodies  exist  in 
their  natural  state.  The  first  is  exercised  upon  masses 
of  matter ;  the  second,  upon  those  molecules  of  which 
masses  are  composed.  The  one  is  the  general  law  of  at- 
traction, or  gravitation;  the  other,  the  law  of  affinity, 
or  chymical  attraction. 

The  law  of  affinity  (the  only  one  of  which  I  shall  now 
speak)  tends  constantly  to  draw  together  the  particles 
of  which  bodies  are  composed.  If  this  force  acted 
alone,  the  degrees  of  density  exhibited  by  bodies  in  their 


INTRODUCTION.  XT 

natural  state  would  depend  entirely  upon  the  degrees  of 
affinity  existing  between  their  component  particles.  But 
its  action  is  balanced  and  modified  by  that  of  the  fluid  of 
heat,  which  enters,  in  various  proportions,  into  all  sub- 
stances, and  which  tends  to  separate,  one  from  another,  the 
elements  which  affinity  draws  together.  Affinity,  alone, 
would  form  only  solid  masses,  inactive,  and  more  or  less 
compact.  The  action  of  heat,  alone,  would  produce  only 
gases,  or  aerial  substances.  But  the  combined  action  of 
these  agents  presents  to  us  bodies  either  in  a  solid,  liquid, 
or  fluid  state,  according  to  the  degree  of  intensity  with 
which  one  or  the  other  force  acts  upon  the  component 
parts.  The  natural  state  of  bodies,  then,  is  owing  to  the 
combined  action  of  the  law  of  affinity,  which  brings  their 
particles  into  union,  and  the  interposing  fluid  of  heat, 
which  separates  them  from  each  other. 

The  variations  which  the  atmosphere  undergoes  during 
the  different  seasons  of  the  year  are  sufficient  to  produce 
changes  of  consistency  in  some  bodies.  Water,  for  in- 
stance, is  either  solid,  liquid,  or  aeriform,  according  to  the 
temperature  of  the  air. 

Man,  who  governs  the  power  of  heat  at  his  pleasure, 
can  produce  all  these  remarkable  changes  in  the  natural 
state  of  bodies.  He  can  augment  or  diminish  their  con- 
sistency at  his  will,  and  cause  them  to  assume  either  the 
solid,  liquid,  or  gaseous  form,  according  as  he  adds  or 
takes  away  that  fluid. 

The  changes  produced  by  the  addition  or  subtraction 
of  heat  are  not  permanent.  The  body  returns  to  its 
natural  state,  the  moment  the  cause  has  ceased  to 
operate, — ^imparting  to  the  surrounding  substances  the 
excess  of  fluid  it  has  imbibed,  or    receiving  from  them 


XVI  INTRODUCTION. 

that  of  which  it  has  been  deprived.  These  aherations 
of  form  and  consistency  do  not  affect  the  nature  of 
bodies;  but,  by  bringing  into  contact  or  separating  the 
molecules  of  which  they  are  composed,  they  augment 
or  diminish  their  cohesion  and  their  affinity,  and  thus 
dispose  them  to  form  new  combinations. 

The  principles  which  I  have  just  explained  are  not 
rigorously  applicable  to  animal  and  vegetable  substances, 
nor  to  some  other  compound  bodies,  except  so  far  as 
the  effects  of  a  low  degree  of  heat  are  concerned.  The 
constituent  principles  of  such  bodies  do  not  all  require 
the  same  degree  of  heat  to  cause  them  to  pass  to  the 
liquid  or  gaseous  state.  It  follows,  then,  that  some  of 
them  can  take  the  one  or  the  other  of  these  forms,  by  any 
degree  of  heat  above  that  of  the  atmosphere,  and  thus 
be  separated  from  those  which  remain  fixed.  In  this 
case  decomposition  is  produced. 

If  the  force  of  affinity  were  the  same  amongst  all  the 
elementary  particles  of  which  various  bodies  are  com- 
posed, there  would  be  only  confused  aggregations  of 
matter,  throughout  all  the  operations  of  nature  and  art. 
But  each  element  has  its  peculiar  affinities,  which  enable 
it  to  enter,  more  or  less  closely,  into  combination  with 
certain  other  elements,  whilst  it  strongly  resists  a  union 
with  those  for  which  it  has  no  affinity.  All  matter  is 
formed,  governed,  and  separated,  according  to  these 
different  affinities.  The  uniform  reproduction  of  the 
combinations  of  art  and  the  productions  of  nature  is 
derived  from  this  principle. 

It  follows  from  the  preceding  statement,  that  the  force 
of  affinity  alone  can  hold  in  lasting  combination  the  par- 
ticles of  matter, — and  that  bodies  are,  even  then,  liable 


INTRODUCTION.  XVll 

to  decomposition ;  for,  according  to  the  laws  of  elective 
affinity,  one  constituent  of  a  compound  body  will  forsake 
another,  for  which  it  has  a  certain  degree  of  affinity,  to 
unite  itself  with  a  third,  for  which  its  affinity  is  stronger. 
We  thus  see  how  important  it  is,  for  those  who  wish  to 
study  the  operations  of  art  and  nature,  to  be  acquainted 
with  the  degrees  of  affinity  that  exist  amongst  the  various 
elementary  bodies  which  enter  into  combination.  Whilst 
the  chymist  influences,  according  to  his  will,  nearly  all 
the  agents  which  are  employed  by  nature,  she  can  follow 
him  in  her  labors,  even  when  she  cannot  imitate  him  in 
her  productions.  She  knows  the  materials  which  the 
chymist  employs,  and  can  often  furnish  them  to  him,  and 
facilitate  his  operations.  She  can  foresee  his  mistakes, 
and  cautiously  turn  aside  the  causes  which  would  pro- 
duce them.  In  a  word,  the  mutual  action  exercised  by 
bodies  is  constantly  regulated  by  the  immutable  laws  of 
nature.  But  the  chymist  can  at  pleasure  dispose  of  these 
same  bodies  of  which  he  knows  the  respective  affinities. 
He  can  combine  them  in  all  their  proportions,  submit 
them  to  all  degrees  of  heat,  and  subject  them  to  the 
action  of  external  agents,  the  energy  of  which  he  can 
increase  or  diminish  to  almost  any  extent,  and  thus 
produce  results  which  nature,  in  her  constant  and  unde- 
viating  march,  cannot  give  rise  to.  It  is  by  means  of 
this  power,  that  chymistry  forms,  every  day,  new  com- 
positions, and  that  she  has  enriched  industry  and  econo- 
my with  a  vast  variety  of  productions,  which,  without 
the  assistance  of  this  science,  would  have  been  for  ever 
unkno\vn. 

Rude  and  inorganic  matter  obeys  no  other  laws  than 
those  of  which  I  have  spoken.    All  the  changes  which  it 

B 


XVlll  INTRODUCTION. 

experiences,  all  the  phenomena  which  it  presents,  all  the 
combinations  and  decompositions  which  take  place  in  it, 
result  from  thegi.  Chymistry  can  foresee  ami  explain 
the  consequences  of  their  action.  She  can  even  pro- 
duce, by  her  exertions,  new  combinations. 

In  addition  to  the  laws  of  affinity,  which  govern  inor- 
ganic matter,  living  bodies  are  subject  to  other  laws, 
which  continually  modify  the  action  of  the  first.  These 
laws  of  vitality  are  energetic,  and  govern  the  law  of 
affinity  in  proportion  to  the  perfect  organization  of  the 
body.  It  is  this,  which  causes  the  mode  of  action  in  living 
bodies  to  escape  our  researches  ;  so  that,  although  wit- 
nesses of  all  which  passes  in  these  bodies,  we  can  neither 
explain  nor  imitate  their  productions.  The  science  of 
phymistry  is  limited  to  a  knowledge  of  the  substances 
which  enter  into  animals  and  vegetables,  to  serve  them 
for  nourishment;  and  to  the  study  of  all  the  agents 
which  aid  them  in  the  performance  of  their  functions. 
She  knows  what  these  bodies  appropriate  to  their  use, 
and  what  they  reject.  But  the  mode  of  elaboration 
by  their  organs,  the  formation  of  their  products,  and  the 
manner  of  their  growth,  is,  and  must  for  a  long  time  be, 
a  mystery  to  us.  That  which  we  already  know  of  the 
functions  of  living  bodies,  is  much  ;  but  that  of  which  we 
are  ignorant,  far  exceeds  it. 

The  laws  of  vitality,  like  all  the  other  laws  of  nature, 
are  unchangeable.  But  their  action  is  varied  in  living 
bodies  by  a  difference  in  organization ;  in  the  same 
manner  as  the  products  vary  in  each  species,  and  in 
each  one  of  their  organs.  It  is  this  variety  of  productions 
which  surprises  us, — especially  when  we  consider,  that 
their  form  and  their  quality  are  constantly  renewed  every 
year,  and  with   every  generation. 


INTRODUCTION.  XIX 

These  laws  of  organization  have,  then,  set  the 
bounds,  over  which  science  has  not  yet  been  able  to 
pass.  She  has,  however,  opened  to  our  view  some  sub- 
lime pages  of  the  book  of  nature ;  and  she  has  made 
many  and  useful  applications  of  their  contents. 

The  living  plant,  fixed  by  its  root  to  an  immovable  soil, 
has  no  power  of  motion  to  enable  it  to  seek  its  support 
from  distant  substances.  It  derives  all  its  nourishment 
from  the  earth  and  air  by  which  it  is  surrounded.  These 
aliments  are  elaborated  in  the  organs  of  the  plant.  They 
are  there  decomposed  and-  combined  with  its  elements, 
in  a  regular  and  uniform  manner.  With  the  dead  plant, 
the  case  is  widely  different.  Upon  that,  other  bodies 
exercise  an  action  entirely  physical.  When  organization 
ceases  to  modify  their  effects,  the  same  agents,  such  as 
air,  water,  and  heat,  which  assisted  it  in  performing  its 
functions  whilst  living,  concur  powerfully  in  decompos- 
ing it  when  deprived  of  vitality  ;  and  complete  disorga- 
nization can  only  be  prevented  by  secluding  it  entirely 
from  the  contact  and  action  of  these  bodies. 

It  is  at  this  period,  that  chymistry  can  exercise  its 
power  with  full  effect.  She  knows  the  elements  that 
enter  into  the  composition  of  the  dead  plant ;  she  knows 
the  various  degrees  of  affinity  by  which  they  are  united, 
and  can  predict  with  certainty  the  changes  which  will 
follow  from  the  action  of  those  external  agents,  which 
she  can  modify  at  her  will. 

From  the  observation  of  these  circumstances,  it  is  my 
opinion,  that  the  knowledge  of  chymistry  can,  with  ad- 
vantage, be  applied  to  the  labors  of  the  agriculturist.  I 
believe,  that,  by  a  better  acquaintance  with  the  bodies 
subject  to    his  management,  by  uniting  well-established 


XX  INTRODUCTION. 

facts  to  a  sound  theory,  by  determining  with  care  the 
effects  of  all  those  bodies  which  can  exert  any  influence 
upon  vegetation,  and  the  modes  of  their  action,  we  shall 
be  able  to  deduce  principles,  the  application  of  which 
will  greatly  accelerate  the  progress  of  the  most  impor- 
tant of  our  arts. 

I  All  the  sciences  have  a  natural  course  from  which 
they  never  deviate  :  they  begin  by  collecting  and  prov- 
ing facts  ;  and  when  these  facts  are  well  established,  they 
compare  them  with  each  other,  and  deduce  from  them 
principles  of  general  application. 

The  facts  in  agriculture  are  already  numerous;  but 
have  the  modifications  wrought  by  the  nature  of  the 
soil,  the  action  of  manures,  the  state  of  the  atmosphere, 
the  influence  of  climate,  and  the  varieties  of  exposure, 
been  sufficiently  attended  to?  Will  a  fact  observed  in 
one  place  be  constantly  reproduced  in  another  ?  Since 
such  is  not  the  case,  we  must  necessarily  come  to  the 
conclusion,  that  solitary  facts  are  not  sufficient  to  estab- 
lish principles  in  agriculture.  It  is  necessary  that  they 
should  have  been  observed  and  verified,  under  the  in- 
fluence of  all  the  agents  of  which  I  have  spoken ;  and 
that  we  should  know  jhe  modifications  which  each  one 
produces,  in  order  to  be  able  to  draw  from  them  general 
and  practical  consequences.  If  the  agents  of  vege- 
tation  were   constantly  tlie   same,  if  their   effects  were 

j/  everywhere  the  same,  one  fact  alone  would  be  sufficient 
to  establish  a  principle,  applicable  to  all  localities ;  but 
the  difference  of  their  action  under  different  circum- 
stances necessarily  produces  important  changes  in  their 
results  :  and  this  it  is,  that  causes  the  kind  of  agriculture 
which  prospers  in  one  country,  to  be  unsuccessful  in  an- 


INTRODUCTION.  XXI 

Other;  and  an  agriculturist,  who  wishes  to  try  methods 
of  cultivation  which  have  succeeded  elsewhere,  often 
finds  himself  deceived  in  his  expectations,  because  he 
cannot  unite  the  same  circumstances  to  ensure  success. 

I  have  thought  that  a  work  upon  the  principles  of  ag- 
riculture, which  should  make  known  the  properties  and 
actions  of  the  several  agents  which  influence  the  results 
of  its  operations,  would  be  really  useful ;  and  accordingly 
I  have  applied  myself  to  forming  an  acquaintance  with 
the  most  usual  methods  of  cultivation,  in  order  that  I 
might  extend  the  application  of  them  to  other  cases  to 
which  they  might  be  suited. 

But  it  is  not  sufficient  to  enlighten  the  agriculturist,  in 
order  to  facilitate  the  progress  of  the  art ;  the  government 
has  an  important  duty  to  perform  towards  it.  It  is  only 
when  intelligence  and  encouragement  are  united,  that 
the  farmer  can  be  assured  of  lasting  prosperity. 

Agriculture  is  the  most  fruitful  source  of  the  riches 
of  a  country,  and  of  the  "welfare  of  its  inhabitants ;  and 
it  is  only  as  the  state  of  agriculture  is  more  or  less  flour- 
ishing, that  we  can  judge  unerringly  of  the  happiness  of 
a  nation,  or  of  the  wisdom  of  its  government.  The  pros- 
perity which  a  country  derives  from  the  industry  and 
skill  of  its  artisans,  may  be  but  a  passing  gleam  ;  that  alone 
is  durable,  which  has  its  rise  in  a  good  cultivation  of  the 
soil.  These  facts  ought  to  be  constantly  present  to  the 
mind  of  the  government,  and  to  influence  all  its  measures. 

A  government  awake  to  its  true  interests  will  seek  to 
facilitate  and  increase  the  cultivation  of  the  soil,  and  to 
open  new  channels  for  the  disposal  of  its  products.  It 
will    protect   property,  by  causing   its    rights    to  be  re- 


XXU  INTRODUCTION, 

spected,  and  punisliing  breaches  of  the  laws  concerning 
it ;  and  it  will  guarantee  the  proprietor  against  arbitrary- 
exactions.  The  taxes  should  be  regulated  in  such  a 
manner  as  to  take  from  the  agriculturist  only  a  portion 
of  the  increase  arising  from  his  labors  ;  for,  if  he  have 
no  surplus  over  his  immediate  wants,  there  will  remain 
to  him  neither  the  means  of  improving  his  modes  of  cul- 
tivation, nor  of  supporting  his  family  with  comfort ; 
neither  will  it  be  possible  for  him  to  renew  his  stock  of 
domestic  animals,  nor  to  augment  their  number.  Any 
government  which  does  not  leave  to  the  farmer  a 
great  part  of  the  profits  proceeding  from  his  harvests, 
soon  puts  a  stop  to  the  production  of  them,  and  thus  real- 
izes the  fable  of  the  goose  with  golden  eggs. 

By  encouraging  improvements  in  agriculture,  and  fa- 
voring the  increase  of  production,  government  enriches 
the  agriculturist  less  than  its  own  revenues ;  since  by 
these  means  the  quantity  of  taxable  matter  is  increased, 
and  the  right  of  government  recognised  under  all  its 
forms,  whether  the  article  produced  be  employed  in  its 
crude  state  for  domestic  use,  or  whether  it  furnish  the 
workshop  of  the  artisan  with  the  materials  of  his  handi- 
craft. 

Though  the  territorial  imposts  have  been  much  dimin- 
ished within  a  few  years,  they  are  still  far  too  high  for  the 
prosperity  of  agriculture.  A  bad  harvest,  a  mortality 
amongst  the  animals  upon  a  domain,  or  a  prevailing  ep- 
idemic, exhausts  the  scanty  store  which  the  economy  of 
the  farmer  had  enabled  him  to  reserve  from  a  favorable 
season ;  and  thus  the  greater  part  of  them  are  forced 
to   contract    debts.     A  succession  of  abundant  harvests 


INTRODUCTION.  XXlll 

hardly  enables  them  to  repair  the  loss  sustained  from  the 
calamities  of  a  year.  The  peasant,  everywhere,  lives 
only  from  day  to  day,  because  he  has  no  capital,  and 
his  poverty  does  not  permit  him  either  to  provide 
against  or  repair  a  misfortune. 

The  government  of  this  country  has  been  often  occu- 
pied with  the  project  of  clearing  those  wild  lands  of 
which  a  part  of  it  consists ;  it  has  even  made  some  at- 
tempts, and  been  at  some  expense,  to  carry  these  plans 
into  execution,  k  would  have  been  wiser  to  excite  and^ 
encourage  the  improvement  of  those  lands  already  under  >''*  | 
cultivation  ;  and  by  this  course  the  best  results  would 
infallibly  have  been  obtained.  These  enterprises,  in  a 
country  where  the  cultivation  of  good  land  has  not  ar- 
rived at  perfection,  belong  to  the  province  of  individual 
speculation,  which  never  fails  to  execute  them,  provided 
it  sees  any  chance  of  success. 

Agriculture  has  for  a  long  time  required  a  law,  which 
should  specially  encourage  improvements,  and  effect  the 
clearing  of  uncultivated  grounds  ;  this  law  should  fix  for 
the  future,  in  a  permanent  and  invariable  manner,  the 
taxes  0T\  land  brought  into  cultivation,  so  that  they  never 
should  be  raised  on  account  of  their  produce  or  the  value 
which  has  been  bestowed  on  them  by  labor  and  indus- 
try. The  fear  alone,  that  taxation  will  sooner  or  later 
be  extended  to  improvements,  is  sufficient  to  turn  the 
current  of  capital  from  that  all-important  employment, 
and  to  throw  it  upon  those  operations  and  speculations 
which,  for  the  most  part,  employ  property  in  ways  that 
are  of  no  advantage,  either  to  the  nation  or  to  the  gov- 
ernment. 


XXir  INTRODUCTION. 

Another  law  not  less  required  by  the  interests  of  ag- 
riculture and  society,  is  one  having  for  its  object  the  en- 
couragement of  planting  forests,  and  the  preservation  of 
those  which  now  exist ;  without  some  law  to  this  effect, 
a  future  and  not  distant  period  threatens  their  entire  de- 
struction. Without  doubt  private  interest,  more  active 
perhaps  in  our  day,  the  division  of  property,  and  the  loss 
of  great  territorial  fortunes,  have  prepared  the  way  for 
and  brought  on  these  consequences  ;  but  the  law  has  con- 
tributed more  than  anything  else  to  produce  them.  In 
fact  a  proprietor  pays  every  year  a  tax  levied  upon  the 
trees  of  his  domain,  and  it  is  easy  for  him  to  calculate, 
that  it  is  more  advantageous  for  him  to  fell  those  of 
twenty  years'  growth,  than  to  leave  them  to  attain  the 
age  of  one  or  two  centuries. 

A  good  law  regarding  district  roads  would  be  a  great 
benefit  to  the  inhabitants  of  the  country ;  easy  transpor- 
tation by  means  of  convenient  roads  is  constantly  re- 
paying to  the  farmer  the  expense  which  he  must  be  at  in 
making  and  preserving  them ;  since  they  will  enable  his 
cattle  to  perform  the  same  quantity  of  labor  at  a  much 
less  expense  of  time  and  strength.  But  it  is  difficult  to 
obtain  from  the  administration  these  important  local  im- 
provements. The  mayors,  their  assistants,  and  the 
members  of  the  municipal  councils,  are  generally  the 
richest  proprietors  of  a  district ;  and  they  never  condemn 
themselves,  either  to  restore  to  the  public  ways  the  en- 
croachments they  have  permitted  to  be  made  upon  them, 
or  to  furrow  their  fields  by  roads,  or  to  support  nearly 
the  whole  expense  which  these  labors  for  the  public 
good  would  require.     There  should  be  attached  by  law 


INTRODUCTION.  XXV 

to  each  department,  a  pupil  of  the  School  of  Bridges 
and  Highways,  who,  a  stranger  to  any  particular  local  in- 
terest, should  lay  out  district  roads,  determine  their  width, 
compel  each  proprietor  to  confine  his  boundaries  within 
their  original  limits,  prepare  plans  and  schemes,  and 
prescribe  the  suitable  materials  to  be  employed  in  the 
execution  of  them.  The  labors  of  this  engineer  should 
be  subject  to  the  inspection  of  the  engineer  of  the  arroiv- 
dissementj  and  to  the  approbation  of  the  chief  engineer ; 
upon  the  report  of  this  last,  the  prefect  should  order  the 
proposed  plans  to  be  carried  into  execution.  The  com- 
munes should  then  provide  for  defraying  the  necessary 
expenses,  in  such  a  manner  as  might  be  least  burden- 
some, and  present  the  result  of  their  deliberations  to  the 
prefect  for  his  approval. 

Canals  and  highways  are  for  society  at  large  what 
by-roads  are  for  the  separate  portions  of  it.  These, 
grand  means  of  communication  may  be  called  the  arte- 
ries of  the  social  body,  conveying  life  through  all  its 
parts.  One  of  our  most  profound  writers  has  said,  that 
"  rivers  and  navigable  streams  are  roads  which  travel ; " 
but  canals  present  great  advantages  over  navigable  riv- 
ers ;  they  go  to  seek  the  productions  of  a  country  in  the 
places  of  their  origin  ;  their  direction  is  always  governed 
by  the  necessity  of  such  means  of  intercourse  ;  their 
navigation  is  easy,  regular,  and  safe ;  they  animate  and 
give  life  to  all  the  country  through  which  they  pass,  with- 
out ever  counterbalancing  these  advantages  by  the  rav- 
ages of  an  inundation. 

By  diminishing  the  expense  of  transportation,  bjc 
opening  communications  with  the  distant  portions  of  a 
country,   by    facilitating  the   exchange   of  articles,    and 


XXVI  INTRODUCTION. 

rendering  common  to  a  whole  nation  the  production  of 
each  locahty,  all  the  sources  of  public  wealth  and  pros- 
perity are  multiplied.  By  an  increased  intercourse  be- 
tween men  civilization  is  perfected;  intelligence  and 
urbanity  of  manners  find  their  way  into  the  most  se- 
cluded spots ;  and  the  law  which  has  established  a  great 
system  of  inland  navigation  in  France,  will  excite  the 
gratitude  of  all  future  ages. 

If  agriculture  requires  some  new  laws  favorable  to 
her  interests,  she  also  demands  the  suppression  of  a 
small  number  which  are  opposed  to  them.  The  law 
should  protect  and  favor  exchanges;  and  government 
ought  to  view  in  this  operation  only  the  mutual  accom- 
modation arising  to  the  proprietors  of  the  property  ex- 
changed, and  not  to  collect  any  duties  excepting  from 
the  profits  on  what  is  exchanged.  By  facilitating  and 
encouraging  exchanges  government  would  do  much  for 
agriculture;  scattered  and  disjointed  property  would  in- 
sensibly become  collected  around  the  dwelling  of  the 
owner;  the  inspection  of  it  would  thus  be  rendered 
easy,  and  a  better  system  of  management  might  be 
adopted  without  difficulty;  transportation  would  be  fa- 
cilitated and  rendered  less  expensive;  the  laboring  ani- 
mals would  suffer  less  from  fatigue,  and  their  quantity 
of  work  be  increased  in  value. 

Another  advantage  arising  from  the  exchange  of 
property  is  that  of  annexing  to  some  estates  small  por- 
tions of  land  lying  contiguous  to  them,  which,  from  their 
limited  extent,  do  not  give  scope  to  the  exercise  of  all  the 
resources  of  good  husbandry.  These  exchanges  would 
likewise  have  the  good  effect  of  extinguishing  a  thou- 
sand disputes,  which  are  constantly  arising  amongst  the 


INTRODUCTION.  XXVU 

proprietors  of  real  estate,  about  limits,  usurpations,  and 
encroachments. 

But  the  greatest  benefit  which  government  can  confer 
on  agriculture,  is  without  doubt  the  suppression  of  the 
duty  upon  salt.  During  those  years  in  which  the  sale 
of  salt  was  free  from  duty,  the  borders  of  the  Mediter- 
ranean were  covered  with  salt-works  ;  immense  capitals 
were  employed  in  forming  these  establishments,  and  they 
sold  salt  to  the  amount  of  twenty  millions  of  francs 
per  year.  The  tax  has  given  a  death-blow  to  this  beau- 
tiful scene  of  industry  ;  nearly  all  the  salt-works  are 
abandoned.  The  consumption  of  salt  has  been  so  much 
reduced,  that  the  price  of  fifty  kilogrammes  (1  cwt.) 
is  not  above  twenty-five  centimes  in  the  salt-pits;  and 
the  duty  upon  as  much  salt  as  is  sold  for  one  million 
five  hundred  francs,  produces  to  the  treasury  from  forty- 
five  to  sixty  millions. 

In  order  to  realize  all  the  evil  which  results  to  agri- 
culture from  the  duty  upon  salt,  it  is  sufficient  to  know 
the  extensive  advantage  arising  from  its  employment. 

Salt  is  of  the  utmost  importance  to  all  ruminating  ani- 
mals, increasing  their  relish  for  their  insipid  food,  excit- 
ing the  action  of  their  membranous  and  weak  stom- 
achs, and  preventing  those  obstructions  of  the  intestines 
which  are  produced  by  the  use  of  dry  forage  during  the 
winter.  It  is  generally  observed  that  those  animals  are 
preferred  in  the  market,  which  have  been  habitually  fed 
upon  saline  plants,  and  that  their  flesh  is  of  a  superior 
quality.  There  is  no  farmer,  who  has  not  been  able  to 
see  the  diflference,  at  the  close  of  a  winter,  between 
those  animals  which  have  received  their  supply  of  salt 
and  those  that  have  been  deprived  of  it ;  the  first  are  well 


XXVlll  INTRODUCTION. 

shaped,  large,  and  fat;  their  hair  is  glossy,  their  eyes 
lively,  and  their  motions  prompt  and  firm :  the  second 
present  images  of  suffering  and  misery ;  the  sheep  have  lost 
nearly  all  their  fleece  before  shearing  time,  and  that  which 
remains  is  falling  from  them  in  locks  ;  the  neat  cattle  are 
lean  and  sickly,  their  organs  of  digestion  are  impeded 
in  their  action,  and  it  is  only  after  having  browsed  the 
juicy  herbage  of  spring  that  they  recover  their  health. 

During  the  time  that  salt  was  freed  from  any  impost, 
the  use  of  it  in  agriculture  became  each  year  more  ex- 
tensive; it  was  mixed  with  manures,  to  increase  their 
activity ;  it  was  spread  at  the  roots  of  trees,  to  reani- 
mate their  languishing  powers  of  vegetation ;  and  the 
quantity  of  salted  provisions,  both  for  market  and  for 
home  consumption,  was  much  increased. 

The  impost  upon  salt  is  to  agriculture  a  real  calamity, 
since  it  has  taken  from  it  many  of  its  sources  of  pros- 
perity ;  and  at  the  same  time  the  public  treasury  has 
received  no  advantage  from  the  tax,  equal  to  the  injury 
which  it  has  inflicted  upon  agriculture. 

I  know  that  in  a  well-organized  state,  the  receipts 
ought  to  cover  the  expenditures ;  and  that  it  is  not 
possible  to  repeal  a  tax  of  forty-five  millions  of  francs, 
without  replacing  it  by  another  equally  productive  ;  but, 
in  selecting  objects  for  taxation,  those  ought  to  be  taken 
which  will  fall  least  heavily  on  the  interests  of  those 
who  pay  them ;  and  it  must  be  prudent  to  avoid  those 
which  will  lessen  production,  and  check  improve- 
ments in  industry,  commerce,  and  agriculture.  In 
establishing  a  tax  it  is  likewise  necessary  to  look  for- 
ward and  to  reason  upon  the  future  effects  of  it ; 
a    tax  which  will  produce  ten  millions,    may   impover- 


INTRODUCTION.  XXIX 

ish  a  nation  more  than  one  of  fifty,  and,  beyond  the 
amount  of  ten  millions,  become  a  scourge ;  for,  the 
government  which  stifles  reproduction,  opposes  the  de- 
velopement  of  industry,  and,  being  reduced  to  live  upon 
its  capital,  -will  very  soon  partake  of  the  public  poverty. 
By  whatever  impost  the  tax  upon  salt  may  be  replaced, 
I  doubt  whether  one  can  be  found  more  injurious  in  its 
effects.  All  the  complaints  that  are  made  in  regard  to 
the  revenue  ought  to  be  directed  against  this  duty ; 
and  in  order  to  hasten  the  suppression  of  it  in  the  coun- 
try, the  tax  might  be  kept  up  on  the  consumption  of 
th&  towns,  where  salt  forms  but  a  small  part  of  the 
expense  of  each  household. 

There  is,  at  this  day,  much  inquiry  whether  the  divi- 
sion of  landed  property  is  favorable  or  injurious  to  agricul- 
ture. This  division  is  the  necessary  consequence  of  the 
partition  of  successions  in  a  direct  line,  and  of  the  sale 
of  detached  portions  of  great  estates.  The  question  of 
the  division  of  property  has  its  supporters  and  its  op- 
posers  ;  but  I  believe  that  it  is  from  not  'having  viewed 
the  subject  in  its  true  light,  that  opinions  in  regard 
to  it  are  still  divided.  Wherever  labor  is  abundant; 
wherever  the  cultivation  of  grain  and  of  artificial  fodder 
cannot  be  carried  to  its  full  extent ;  wherever  the  nature 
of  the  soil  admits  only,  or  mostly,  of  the  cultivation  of 
the  vine,  there  the  division  of  property  is  advantageous. 
The  impossibility  of  feeding  animals  for  labor,  in  such 
situations,  calls  the  arm  of  man  into  use  to  supply  their 
place;  and  the  husbandry  on  a  small  scale  thus  prac- 
tised, fertilizes  a  soil,  which  would  otherwise  remain 
sterile.  A  small  estate,  placed  in  the  hands  of  an  in- 
dustrious and  intelligent  man,  will  always  produce  more 


XXX  INTRODUCTION. 

than  if  it  were  annexed  to  an  extensive  domain.  The 
children  of  the  proprietor  of  a  small  farm  will  collect 
manure  for  the  fields,  or  clear  them  from  noxious 
weeds  :  the  father  of  the  family  will  till  the  soil  with 
care,  and  at  the  most  favorable  seasons ;  he  will  not 
leave  a  corner  of  his  ground  unproductive.  Under  this 
kind  of  management  four  or  five  acres  of  well-cultivated 
land  is  sufficient  for  the  maintenance  of  a  family ;  whilst 
fifty,  in  a  farm,  the  labors  of  which  are  carried  on  upon 
a  large  scale,  requiring  the  assistance  of  animals,  will 
scarcely  support  five  or  six. 

If  we  consider  the  division  of  property  in  its  moral 
relations,  we  shall  find  its  advantages  greatly  increased. 
The  laborer  without  property  has  no  country  ;  he  remains 
fixed  to  no  point  excepting  by  habit ;  his  means  of  subsist- 
ence are  everywhere,  where  he  can  employ  his  strength ; 
the  laws  are  for  him  only  modes  of  oppression ;  disor- 
der and  insurrection  present  to  him  some  chance  of 
ameliorating  his  condition,  and  he  is  always  at  the  dis- 
posal of  those  who  will  pay  him  best. 

Landed  property,  whether  it  be  extensive  or  not,  by 
attaching  the  owner  of  it  to  the  soil,  causes  him  to  love 
the  government  which  protects  it,  and  to  respect  the 
laws  which  guarantee  its  possession.  Since  the  num- 
ber of  proprietors  of  land  in  France  has  been  tripled, 
the  leaders  of  insurrectbn  amongst  the  people  have  not, 
in  the  country,  found  any  support. 

In  a  neighboring  kingdom,  where  they  count  scarcely 
twenty-five  proprietary  families,  and  where  manufacturing 
industry  employs  the  greater  part  of  the  population,  the 
government  is  obliged  to  levy  a  tax  of  nearly  three  hun- 
dlj^e.(J.milJ^pns  of  francs,  in  order  to  give  bread  to  the  va- 


INTRODUCTION.  XXXI 

grant  portion  of  the  community,  and  thus  to  secure  the 
public  tranquillity.  In  Spain,  where  the  nobility  and  cler- 
gy possess  nearly  all  the  landed  property,  we  see  the  pop- 
ulation besieging  the  gates  of  the  castles  and  convents,  to 
ask  alms  from  the  monks  and  nobles.  Without  doubt 
the  greater  part  of  the  wealthy  are  not  insensible  to  the 
cries  of  misery  which  surround  them ;  but  it  is  surely 
better  for  each  one  to  derive  his  subsistence  from  his 
own  resources,  than  to  beg  it  from  another.  I  do  not 
pretend,  that  it  would  be  of  advantage  to  divide  all  the 
French  territory  into  small  estates,  or  to  reduce  it  every- 
where to  the  mode  of  culture  adapted  to  them :  those 
portions  of  country,  which  admit  of  the  full  develope- 
ment  of  great  agricultural  resources,  ought  to  be  covered 
with  farms  of  an  extent  sufficient  to  unite  all  the  means 
necessary  to  call  them  into  action.  It  is  not  ex- 
pected that  it  will  be  possible,  except  on  these  great 
farms,  to  raise  cattle,  or  to  supply  all  the  requisites  of 
life  for  the  markets.  The  present  state  of  things  has 
established  itself  by  its  own  fitness :  the  difference  be- 
tween those  portions  of  country  suited  to  great,  and 
those  adapted  to  small  cultivation,  is  so  well  felt,  that 
the  division  of  real  estate  into  small  farms  is  only  found 
in  the  last.  Private  interest  has  placed  the  bounds  of 
the  subdivision  of  territory  ;  and  it  can  be  safely  left  to 
that  great  mover  of  the  conduct  of  men,  to  stop  the 
further  division  at  that  moment,  when  the  processes  of 
labor  can  be  carried  on  with  the  most  ease,  and  to  the 
greatest  advantage.  If  exchanges  should  become  less 
difficult  than  at  present,  there  is  no  doubt  that  contiguous 
portions  of  land,  belonging  to  different  proprietors,  would 
be  united  under  one,  till  a  farm  of  convenient  extent 
ihould  be  formed. 


XXXll  INTRODUCTION. 

The  progressive  steps  in  agriculture  are,  and  ought 
to  be,  slow  ;  and  it  is  contrary  to  the  counsels  of  wisdom 
and  prudence,  to  wish  to  deviate  from  customs  rendered 
sacred  by  time,  until  the  new  modes  to  be  adopted 
shall  have  received  the  sanction  of  successful  experi- 
ment. 

The  reproach,  which  is  every  day  made  to  the  hus- 
bandman, of  his  indifference  towards  new  modes  of 
culture,  appears  to  me  not  to  be  well  founded ;  he 
wishes  first  to  see  and  compare  them  with  the  methods 
to  which  he  has  been  accustomed;  he  has  neither  the 
knowledge,  nor  the  means  of  forming  beforehand  a  just 
estimate,  of  the  advantages  which  they  offer  him ;  he 
perseveres  then  in  his  old  course  till  some  neighbour, 
richer  and  more  enlightened  than  hhnself,  is  able  to  pre- 
sent to  him,  by  the  new  mode,  results  more  advanta- 
geous than  he  has  obtained  from  his  own. 

Example  is  the  only  lesson  profitable  to  a  husband- 
man ;  when  one  is  placed  before  his  eyes,  and  his  reason 
is  convinced  of  its  goodness,  he  is  not  slow  to  follow  it ; 
and  by  no  other  way  than  this,  can  improved  methods 
of  agriculture  be  introduced  and  propagated. 

The  civil  discords  which  have  so  long  agitated  France, 
have  compelled  a  great  number  of  proprietors  to  aban- 
don the  stormy  life  of  the  city,  and  to  establish  them- 
selves in  their  domains,  where  they  direct  the  labors  of 
their  farms ;  agriculture  is  thus  enriched  by  the  intelli- 
gence, the  wealth,  and  the  scientific  views,  which  they 
carry  with  them  to  every  part  of  the  country.  It  is 
much  to  be  desired  that  this  course  should  be  generally 
pursued,  since  it  cannot  but  have  a  happy  effect  upon 
agricultural  prosperity,  and  thus  ultimately  benefit  the 
kingdom  at  large. 


INTRODUCTION.  XXXlll 

Without  doubt  the  superintendence  of  the  labors  on 
an  extensive  domain,  by  an  enlightened  owner,  is  bene* 
ficial  to  the  advancement  of  agriculture ;  and  at  the 
same  time  that  it  is  one  of  the  most  useful,  it  is  one  of 
the  most  delightful  and  noble  of  all  occupations  ;  but 
if  the  improvements,  which  the  proprietor  of  a  large  estate 
can  introduce,  do  not  compensate  for  the  advantages 
which  the  small  proprietor  or  farmer  has  over  him,  the 
former  may  sacrifice  his  interests.  The  proprietors  of 
small  farms  are  constantly  at  the  head  of  the  laborers, 
and  themselves  assist  in  the  performance  of  the  work ; 
they  live  at  small  expense,  attend  fairs  and  markets 
frequently,  and  buy  and  sell  to  advantage ;  they  have 
no  overseers  to  pay,  nor  to  feed  ;  their  wives  and  daugh- 
ters take  care  of  the  poultry-yard  and  dairy,  and  per- 
form the  labors  of  the  house ;  such  are  happy,  when,  at 
the  end  of  a  year,  they  find  some  profit  arising  from  the 
labors  of  themselves  and  families.  The  large  proprie- 
tors, whose  possessions  are  intrinsically  of  greater  value, 
do  not  enjoy  any  of  these  advantages  ;  and,  if  they  do 
not  compensate  for  the  absence  of  them  by  the  exer- 
cise of  a  superior  kind  of  industry,  they  must  Sustain 
loss,  where  the  husbandman  derives  gain.  In  order  to 
ensure  success  in  any  undertaking,  it  is  not  sufl5cient  to 
adopt  a  new  method  of  proceeding.  In  agriculture,  as 
in  every  well-conducted  enterprise,  every  thing  should 
be  calculated,  and  the  operations  to  be  entered  upon 
should  be  regulated  by  a  comparison  of  an  estimate  of 
the  expenses  attending  them,  with  an  estimate  of  the 
profits  which  may  be  rationally  expected  to  arise  from 
them.  Though  a  paradoxical  statement,  it  is  certainly 
true,  that  a  farmer  may  be  ruined  by  a  good  harvest:; 
c* 


XXXIV  INTr.ODUCTIONr 

and  it  is  equally  as  true,  that  agriculture  does  not  re- 
quire unnecessary  expenses ;  on  the  contrary,  she  con- 
demns every  superfluity  as  a  species  of  luxury.  It  is 
from  their  not  being  fully  impressed  with  the  impor- 
tance of  these  principles,  that  we  every  day  see  new 
proprietors  condemn,  almost  without  examination,  usages 
consecrated  by  time  and  accredited  by  good  results,  to 
introduce,  at  great  expense,  innovations  unsuited  to  the 
soil  or  climate.  Being  unable  to  bring  these  into  coope- 
ration with  their  plans,  they  are  obhged  to  abandon  their 
estates  after  having  ruined  their  fortunes. 

One  of  the  causes,  undoubtedly,  which  contributes  rhost 
to  retard  the  application  of  just  principles  to  French  ag- 
riculture, is  the  shortness  of  ihe  leases  ;  which  hardly  al- 
lowing a  farmer  to  become  acquainted  with  the  nature  of 
the  soil,  he  cultivates  it  nearly  at  hazard ;  he  can  neither 
make  any  improvements  in  his  modes  of  dressing  the 
land,  nor  establish  a  good  system  of  cropping ;  he  is 
obliged  to  forego  the  use  of  the  best  kinds  of  grasses,  such 
as  sainfoin  and  clover,  because  he  cannot,  in  a  short 
space  of  time,  prepare  the  land  for  the  reception  of 
them;  neither  can  he  hope  to  reap  the  benefit  of  the 
harvests,  which  they  would,  for  a  long  time,  produce. 
Thus,  however  intelligent  a  farmer  may  be,  he  is  forced 
to  live  from  day  to  day,  and  continue  the  imperfect 
system  of  cultivation  commenced  by  his  predecessors. 
He  is  obliged  to  obtain  from  the  soil  the  utmost  that  it 
can  furnish,  in  the  state  in  which  he  takes  it,  without 
making  any  efforts  to  ameliorate  the  condition  of  the 
soil  ;  since  at  the  end  of  his  lease  he  would  be  liable 
either  to  have  his  rents  raised  in  proportion  to  its  in- 
creased productiveness,  or  to  have  his  lease  taken  from 
him. 


INTRODUCTION.  XXXy 

Whilst  the  cultivation  of  artificial  meadows,  and  the 
sound  doctrine  of  a  rotation  of  crops,  were  unknown,  it 
was  well  to  fix  the  duration  of  leases  to  three  years ; 
then  all  agriculture  consisted  in  two  years  of  corn  har- 
vests and  one  year  of  fallow ;  the  same  course  recom- 
menced every  fourth  year,  and  the  successive  farmers 
followed  this  plan  without  any  deviation ;  there  was 
therefore  no  inconvenience  arising  from  supplying  the 
place  of  one  by  another.  But  at  this  day  it  is  well  known, 
that  the  establishment  of  artificial  meadows,  and  a  good 
system  of  successive  crops,  ought  to  form  the  basis  of 
agricultural  proceedings;  and  it  is  acknowledged,  that 
in  order  to  execute  these  two  great  methods  of  amelio- 
ration, and  to  reap  the  fruits  of  them,  a  term  of  twelve 
or  fourteen  years  is  necessary ;  the  leases  ought,  there- 
fore, to  be  of  at  least  that  duration.  In  cases  like  this, 
the  interests  of  the  proprietor  and  farmer  are  the  same, 
nor  can  they  be  divided  without  injury  to  both.  Ground 
well  tilled  increases  in  value,  and  thus  enriches  both  the 
lessor  and  the  lessee,  whilst  on  those  estates  where  the 
farmer  sees  himself  secure  of  remaining  for  only  three 
years,  he  cannot  employ  either  his  intelligence  or  capital  < 
to  advantage  ;  and  he  continues  the  imperfect  course  of 
management  which  he  has  hitherto  pursued. 

Though  agriculture  has  been  gradually  enriched  by 
the  introduction  of  many  foreign  plants,  it  still  remains 
for  us  to  adopt  and  naturalize  others,  and  to  extend  the 
cultivation  of  those  we  now  possess.  The  agriculture 
which  is  limited  to  the  production  of  grain,  supplies  only 
a  portion  of  the  wants  of  society ;  but  if  it  includes  in 
its  labors  all  the  productions  of  which  the  climate  and 
soil  will  admit  the   cultivation,  it   will  provide  for  the 


XXXVl  INTRODUCTION. 

workshop  of  the  artisan  the  materials  of  his  industry, 
and  thus  supply  every  necessary  of  hfe. 

The  lot  of  the  agriculturist  who  cultivates  only  one 
species  of  produce,  is  always  precarious ;  he  is  dependent 
not  only  upon  the  chances  of  the  harvest,  but  upon  the 
rate  of  sales  and  the  necessities  of  consumers ;  whilst 
he  who  can  procure  from  the  soil  a  variety  of  produc- 
tions, is  nearly  sure  of  obtaining  a  market  for  some  of 
them.  It  is  thus  at  the  south,  where,  independent  of  the 
productions  common  to  all  the  country,  the  large  propri- 
etor has  still  his  harvests  of  wine,  silk,  and  oil,  and  is 
indemnified  by  the  abundance  of  one  of  these  for  the 
mediocrity  of  the  others. 

Another  advantage  resulting  to  the  agriculturist  from 
the  cultivation  of  a  variety  of  productions,  is  the  power 
of  appropriating  each  portion  of  the  land  to  the  vegeta- 
ble for  which  it  is  best  adapted,  and,  by  this  means,  of 
preserving  the  soil  in  good  condition.  This  mode  of  man- 
agement offers  to  the  agriculturist  immense  resources  for 
a  rotation  of  crops  ;  where  only  grains  are  cultivated,  it 
is  impossible  to  establish  a  judicious  succession  of  crops  ; 
since  it  is  only  upon  a  variety  of  productions  that  there 
can  be  founded  that  system  of  rotation  or  succession, 
which  will  preserve  the  land  in  a  constant  state  of  fertil- 
ity, and  permit  it  to  produce  without  interruption.  We 
have  already  introduced  into  agriculture  the  cultivation 
of  grasses,  grains,  oil,  and  roots,  and  have  thus  furnished 
the  materials  for  a  succession  of  crops.  We  have  for  a 
long  time  raised  flax,  hemp,  madder,  and  hops ;  but  we 
are  still  obliged  to  purchase  of  foreign  nations  the  great- 
er part  of  those  articles.  Why  cannot  the  soil  of  France 
furnish   all  we  need  of  them  ?     Neither  land  nor  hands 


INTRODUCTION.  XXXVll 

are  wanting  to  carry  French  agriculture  to  perfection  ; 
the  variety  of  the  cHmate,  the  nature  of  the  soil,  the  in- 
telligence of  the  inhabitants,  all  permit  the  cultivation  of 
nearly  every  thing  which  the  wants  of  society  require. 
In  regard  to  position,  France  enjoys  a  privilege  which 
no  other  nation  can  partake  with  her. 

I  propose  closing  this  work  with  two  treatises;  one 
upon  the  extraction  of  indigo  from  woad,  and  the  othep 
upon  the  manufacture  of  sugar  from  the  beet  root. 
These  two  branches  of  industry  can  yield  to  the  agricul- 
tural interests  of  France  an  annual  product  of  more  than 
a  hundred  millions  of  francs.  I  shall  submit  to  the  agri- 
culturist the  information  which  experience  has  afforded 
in  regard  to  these  new  sources  of  prosperity ;  and  I  do 
not  doubt,  if  he  will  direct  his  attention  to  the  subject, 
that  he  will  appropriate  a  portion  of  the  time  included 
in  his  rotation  of  crops,  to  the  cultivation  of  two  such 
important  articles  of  importation. 

Whilst  endeavouring  to  improve  agriculture  by  applying 
to  it  the  physical  sciences,  I  have  striven  to  avoid  those 
stumblingblocks  which  would  infallibly  have  turned  rne 
aside  from  the  end  which  I  proposed  to  myself  to  attain. 
I  have  endeavoured  to  keep  in  view,  that  I  was  writing 
for  the  agriculturist ;  and  that  consequently  my  work 
ought  to  be  clear,  precise,  and  suited  to  his  understand- 
ing, his  education,  and  his  means.  In  order  to  effect 
this,  I  have  often  borrowed  his  language,  and  I  have 
nearly  always  relied  upon  his  experience  for  the  truth  of 
the  principles  which  I  have  advanced.  Convinced  that 
a  process,  the  results  of  which  have  been  proved,  is 
at  all  times  preferable  to  a  purely  theoretical  statement, 
I  have  uniformly  respected  the  knowledge  acquired  by 


XXXVlll  INTRODUCTION. 

experience,  and  have  proposed  no  new  methods,  except- 
ing those,  the  superiority  of  which  over  the  old  ones  ap- 
peared to  me  to  be  fully  confirmed.  It  is  particularly 
important  in  agriculture  to  be  cautious  of  innovations. 
There  is  not  amongst  husbandmen,  generally  speaking, 
a  sufficient  degree  of  knowledge  to  enable  them  to  ap- 
propriate the  suitable  soil  and  climate  to  foreign  produc- 
tions; their  best  plan  therefore  is,  to  wait  till  some 
neighbour  more  enlightened  than  themselves  can  exhibit 
to  them  specimens  of  improvements ;  which  they  may 
imitate  without  running  much  risk  of  ill  success. 

1  shall  perhaps  be  accused  of  having  permitted  myself 
to  make  some  repetitions,  and  I  candidly  acknowledge 
that  I  have  not  endeavoured  to  avoid  them.  In  a 
work  like  this,  the  subjects  which  are  treated  may  often 
be  presented  under  different  forms ;  their  phenomena 
always  result  from  the  same  principles,  but  they  may 
be  most  clearly  elucidated  by  varying  the  modes  of  ex- 
plaining them.  I  have  treated  each  subject  in  a  manner 
entirely  independent  of  the  rest ;  I  have  called  to  mind 
all  the  facts  that  could  throw  light  upon  it ;  I  have  de- 
duced from  them  those  principles  which  ought  to  direct 
the  agriculturist  in  his  labors ;  and  I  have  not  feared  to 
repeat  a  truth  as  often  as  I  thought  it  could  be  done  with 
advantage.. 

This  work  is  not  perfect,  and  I  can  myself  judge  of 
its  imperfections  better  than  anyone  else;  but,  such  as 
it  is,  I  beUeve  it  will  be  found  useful.  I  trust  that  the 
application  of  the  physical  sciences  to  agriculture  will 
be  extended  in  proportion  as  those  sciences  advance ; 
and  that  a  more  thorough  knowledge  of  the   principles 


INTRODUCTION.  XXXIX 

according  to  which  they  act,  will  occasion  the  rectifica- 
tion of  any  errors  which  may  have  arisen  from  their 
having  been  misapplied.  The  celebrated  Davy,  of  Eng- 
land, has  already  published  a  work  upon  Agricultural 
Chymistry,  from  which  I  have  borrowed  many  excel- 
lent principles :  others  will  do  better  than  we  have 
done. 

Hitherto  the  physical  sciences  have  been  applied 
to  the  other  arts  much  more  than  to  agriculture ; 
many  arts  have,  in  our  day,  been  originated  or  im- 
proved, by  their  means,  whilst  the  progress  made  in  ag- 
riculture has  been  very  trifling.  This  difference  ap- 
pears to  me  to  proceed  from  two  causes  :  the  fir^t  of 
which  is,  that  the  greater  part  of  the  phenomena  offered 
to  us  by  agriculture  are  the  effects  of  the  laws  of  vitali- 
ty, which  govern  the  functions  of  plants,  and  these  laws 
are  still  unknown  to  us  ;  whilst,  in  the  arts  which  are  ex- 
ercised upon  rude  and  inorganic  matter,  all  is  regulated, 
all  is  produced,  by  the  action  either  of  physical  laws  only, 
or  of  simple  affinity,  which  are  known  to  us.  The 
second  cause  is,  that  in  order  to  apply  the  physical 
sciences  to  agriculture,  it  is  necessary  to  study  their  op- 
erations profoundly,  not  only  in  the  closet,  but  in  the 
fields. 

Though  the  proprietor  of  a  large  domain,  of  which  I 
have  for  a  time  directed  the  labors,  I  feel  that  the  facts 
which  I  have  been  able  to  collect  upon  various  subjects, 
are  still  insufficient  for  the  establishment  of  indisputable 
principles  regarding  them ;  and  in  all  such  cases,  I  have 
done  nothing  but  present  to  the  reader  the  doubts  or  the 
simple  probabilities  which  may  have  arisen  from  my  ob- 


INTRODUCTION. 


servations.  I  may  have  committed  many  errors  in  my 
explanations,  but  I  believe  I  have  not  misstated  a  single 
fact ;  and  it  is  in  this  belief  that  I  offer  this  work  to  the 
agriculturist. 


CHYMISTRY 


APPLIED    TO 


AGRICULTURE 


CHAPTER  I. 


GENERAL    VIEWS    OF    THE  ATMOSPHERE,    CONSIDERED    IN    ITS 
EFFECTS    UPON    VEGETATION. 

In  order  to  judge  of  the  influence  which  the  atmosphere 
exercises  over  vegetation,  it  is  necessary  to  be  acquainted 
with  the  peculiar  and  characteristic  properties  of  each  of 
the  elements  of  which  it  is  composed,  and  to  study  their 
action  upon  terrestrial  bodies. 

The  gases,  azote  and  oxygen,  are  the  two  fluids,  of 
which  the  atmosphere  is  essentially  composed  ;  they  are 
found  in  uniform  proportions,  even  in  the  highest  regions 
from  which  they  have  been  brought.  M.  Gay-Lussac  has 
established  this  fact,  by  a  comparative  analysis  of  the  air 
taken  from  a  height  of  twenty-three  thousand  feet,  and  of 
that  which  is  upon  the  surface  of  the  earth. 

There  are  certain  other  fluids,  which  are  uniformly 
found  in  the  atmosphere,  but  in  very  variable  proportions ; 
the  principal  of  these  are  carbonic  acid,  water,  the  elec- 
tric and  magnetic  fluids,  light,  and  heat.  The  two  last 
mentioned  exercise  a  very  marked  influence,  not  only  on 
vegetation,  but  on  all  the  phenomena  which  terrestrial 
bodies  present  to  our  notice ;  and  though  they  do  not 
enter  essentially  into  the  composition  of  the  atmosphere, 
their  action  is  so  closely  united  with  that  of  its  principal 
constituents,  as  to  be  nearly  inseparable  from  them.  In 
order  that  the  action  of  the  atmosphere  may  be  better 
understood,  I  propose  to  treat  separately  of  all  the  fluids  it 
contains,  and  afterwards  to  show  the  phenomena  which 
the  application  of  them  to  agriculture  exhibits. 


iff  ClttMISTRY   APPLIED    TO    AGRICULTURE:, 

ARTICLE  I. 

Of  the  Ponderable  Fluids  contained  in  the  Atmosphere, 

The  ponderable  fluids  contained  in  the  atmosphere  are 
azote,  oxygen,  carbonic  acid,  and  water. 

1.  Azote  constitutes  nearly  four  fifths  of  the  atmospher- 
ic composition,  and  yet,  by  a  singular  caprice  of  nature,  it 
exercises  less  influence  on  the  substances  of  the  three 
kingdoms,  than  any  one  of  the  other  principles  contained 
in  the  atmosphere.  This  gas  is  found  in  small  quantities 
in  some  of  the  products  of  vegetables,  and  abundantly  in 
those  of  animals.  The  presence  of  azote  in  some  of  the 
products  of  vegetation  is  to  be  accounted  for  by  its  pres- 
ence in  the  water,  which  plants  imbibe  from  the  atmo- 
sphere, and  in  those  manures  by  which  plants  are  nour-- 
ished,  and  of  which  it  forms  one  of  the  principal  constitu- 
ents. 

In  animals,  in  which  azote  is  more  abundant  than  in 
plants,  the  food  by  which  they  are  nourished,  and  the  air 
which  is  inhaled  by  respiration,,  concur  equally  to  account 
for  its  presence.  The  .experiments  of  Messrs.  de  Hum- 
boldt and  Provencal  upon  fish ;  Spallanzani  upon  reptiles ; 
and  those  of  Messrs.  Davy,  Pfaff",  Enderson,  Edwards^ 
Dulong,  &c.  upon  man,  leave  no  doubt  as  to  the  absorp- 
tion of  azote  during  respiration ;  but  this  absorption  is 
unequal  and  irregular,  varying  according  to  circumstances  ; 
this  gas  differing  from  oxygen  in  this  particular,  at  least 
in  its  effects  upon  animal  and  vegetable  economy.  The 
action  of  azote  is,  so  far  as  it  is  known,  of  such  trivial  im- 
portance, that  we  are  at  a  loss  to  account  for  the  propor- 
tion which  nature  has  assigned  it  in  the  composition  of 
the  atmosphere.  It  is  supposed  by  some,  that  all  the  gas- 
es, all  the  vapors,  and  all  the  exhalations  which  arise  from 
the  surface  of  the  earth,  form  in  the  atmosphere  an  im- 
mense magazine  of  azote,  which  is  returned  thence  as  it 
is  needed,  either  for  the  support  of  animal  and  vegetable 
life,  or  to  produce  those  phenomena  of  composition  and 
decomposition,  which  are  constantly  renewing  the  surface 
of  the  globe.  The  specific  gravity  of  pure  azote  is  to 
that  of  the  atmosphere  in  the  proportion  of  9,691  to 
10,000. 

2.  Oxygen  gas  forms  about  one  fifth  of  the  atmosphere. 


CHYMISTRY    APPLIED    TO    AGRICULTURE.  3 

The  specific  gravity  of  oxygen  is  to  that  of  the  atmo- 
sphere, as  11,036  to  10,000.  The  effects  produced  by  ox- 
ygen are  equally  numerous  and  important;  it  supports 
animal  life  by  respiration  ;  and  combining  with  the  carbon 
of  the  blood,  it  produces  the  greatest  proportion  of  animal 
heat.  The  germination  of  seeds  is  promoted  by  this  gas, 
and  it  is  absorbed  by  the  leaves  of  plants  during  the 
night :  by  its  combination  with  the  metals  the  oxides  of 
them  are  formed.  It  is  likewise  the  necessary  agent  of 
combustion,  and  concurs  powerfully  in  the  decomposition 
of  all  animal,  vegetable,  and  mineral  substances. 

In  all  cases  where  oxygen  exerts  its  action,  it  combines 
with  some  one  of  the  elements  upon  which  it  acts,  forming 
acids  with  carbon,  azote,  sulphur,  phosphorus,  and  many 
of  the  metals ;  water  with  hydrogen,  «Slc.  The  nature  of 
the  compositions,  of  which  oxygen  is  an  element,  varies 
according  to  the  proportions  in  which  it  enters  into  com- 
bination. 

When  we  survey  the  extent  and  importance  of  the  ope- 
rations performed  by  this  gas,  and  especially  when  we 
consider  that  it  is  constantly  forming  new  bodies,  with 
which  it  afterwards  ceases  to  have  any  coRnexion,  we  are 
almost  led  to  fear,  that  the  atmosphere  must  be,  sooner  or 
later,  exhausted  of  this  active  and  regenerating  principle ; 
but  nature,  we  find,  is  continually  repairing  the  loss  thus 
sustained,  by  the  production  of  equivalent  quantities.  The 
leaves  of  plants,  under  the  influence  of  the  solar  rays, 
pour  forth  into  the  atmosphere  torrents  of  oxygen,  pro- 
duced by  the  decomposition  of  carbonic  acid  and  of  water ; 
of  which  they  appropriate  to  themselves  the  carbon  and 
the  hydrogen. 

It  is  without  doubt  possible,  that  in  many  situations  the 
reproduction  of  oxygen  is  not  in  proportion  to  its  con- 
sumption. This  must  happen  especially  where  great  quan- 
tities are  required  for  respiration,  or  to  support  combus- 
tion. But  this  deficiency  is  only  partial  and  momentary ; 
for  the  great  mobility  of  the  atmospheric  fluid  enables  it, 
almost  immediately,  to  restore  its  equilibrium  from  all 
points.  The  agitation  of  the  winds  mixes  together,  ia 
proportions  nearly  constant,  both  the  elements  of  which 
the  atmosphere  is  composed,  and  the  principal  fluids 
which  are  found  in  it. 

The  creation  or  destruction  of  any  element  is  not  to  be 
found  in  the  operations   of  nature.      The  numerous  phd 


4  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

nomena  of  composition  and  decomposition,  which  take 
place  upon  the  surface  of  the  globe,  present  only  changes 
of  combinations,  which  are  formed  according  to  fixed, 
eternal,  and  unchangeable  laws.  Thus  nature  is  regene- 
rated, without  being  impoverished  ;  and  matter  expe- 
riences only  those  changes  which  are  reproduced  uniformly 
and  periodically,  especially  in  organic  bodies. 

3.  Carbonic  acid  is  found  constantly,  but  in  various 
proportions,  in  the  atmosphere.  Though  much  heavier 
than  azote  or  oxygen,  its  weight  being  to  that  of  the 
latter,  as  1,520  to  1,000,  it  is  found  disseminated  through- 
out the  whole  atmospheric  region.  The  elder  M.  de 
Saussure  has,  by  means  of  lime-water,  drawn  it  from  the 
air  upon  the  summit  of  Mont  Blanc.  From  the  results  of 
all  the  experiments  that  have  been  made,  there  can  be  no 
doubt,  that  the  proportions  of  azote  and  oxygen  in  the 
composition  of  the  atmosphere  are  uniform  and  nearly  in- 
variable ;  and  it  appears  to  be  likewise  proved,  that  car- 
bonic acid  is  also  found  there,  and  at  all  heights,  but  in 
various  proportions. 

M.  Th.  de  Saussure  has  compared  the  different  portions 
of  carbonic  acid  in  the  atmossphere  which  he  has  analyzed, 
and  found  the  difference  between  them,  in  summer  and  in 
winter,  to  be  as  follows. 

IN    WINTER. 

31st  of  January,  1809,  10,000  parts  of  air 

contained   . carbonic  acid  4,570 

2d  of  February,  1811 "  "     4,660 

7thof  January,  1812 "     ,      ''     5,140 

The  mean- term  in  winter  from  10,000  parts  of  air  was. 

In  volume  .     .     .     4,790 

In  weight   ...     7,280 

IN    SUMMER. 

20th  of  August,  1810,  10,000  parts  of  air 

contained carbonic  acid  7,790 

27th  of  July,  1811 "  "     6,470 

15th  of  July,  1815 "  "     7,130 

The  mean  term  in  summer  from  10,000  parts  of  air  was, 

In  volume  .     .     .     7,130 

In  weight    .     .     .  10,830 
Without  doubt,  when  the  air  is  tranquil,  or  when  the 
carbonic    acid,  which  is  produced  so  abundantly  by   fer- 
mentation,  respiration,    combustion,    &c.,    is   retained    in 
confined  places,  the  quantity  of  this  acid  will  exceed  the 


CHTMISTRY    APPLIED    TO    AGRICULTURE.  5 

ordinary  proportion ;  but  from  the  moment  that  the  agita- 
tion of  the  winds  can  mingle  it  with  the  atmosphere,  it 
is  spread  and  diffused  towards  all  points,  according  to  cer- 
tain fixed  laws.  Unless  in  some  extraordinary  cases, 
which  form  exceptions  to  the  general  rule,  carbonic  acid 
exists  in  the  atmosphere  at  most  only  in  the  proportion  of 

Carbonic  acid  is  constantly  absorbed  and  decomposed 
by  the  leaves  of  plants.  The  carbon  is  appropriated  by 
the  plants  to  their  own  support,  and  the  oxygen  is  thrown 
out  into  the  atmosphere.  CarlDonic  acid  combines  with 
the  lime  in  fresh  mortar,  and  causes  it  to  return  to  its 
original  state  of  lime-stone.  Under  the  pressure  of  the 
atmosphere,  water  will  hold  in  solution  nearly  its  own 
volume  of  carbonic  acid,  and  be  slightly  acidulated  by  it; 
but  under  the  force  of  a  greater  pressure,  it  will  contain 
a  much  greater  quantity.  Water,  thus  charged,  froths 
like  Champagne  wine,  which  owes  its  effervescence  to  the 
carbonic  acid  produced  by  the  fermentation  of  the  wine 
in  well-corked  bottles.  In  some  recent  experiments  car- 
bonic acid  gas  has  been  reduced  by  compression  to  a 
liquid  state. 

4.  Water  exists  in  the  atmosphere,  under  the  form  of  an 
elastic  fluid.  When  it  is  absorbed  by  bodies  for  which  it 
has  a  strong  afTmity,  such  as  the  calcined  muriate  of  lime, 
the  portion  of  air  from  which  it  is  taken,  is  diminished  in 
weight  and  volume.  This  has  been  proved  by  the  experi- 
ments of  the  elder  M.  de  Saussure  and  of  Davy.  The 
quantity  of  aqueous  fluid  contained  in  the  air,  varies  ac- 
cording to  the  temperature  of  the  atmosphere,  and  in- 
creases in  proportion  as  that  is  elevated.  At  50^  Fahren- 
heit it  forms  in  volume  nearly  3^^  of  the  atmospheric  fluid ; 
and  as  its  density  is  to  that  of  the  atmosphere  in  the  pro- 
portion of  10  to  15,  it  constitutes  nearly  yL  of  its  weight 
(Davy). 

The  aqueous  fluid  forms,  when  the  atmospheric  tempe- 
rature is  34°  Centigrade  =z  93°.20,  (Davy  says  at  100%) 
^  of  the  volume  of  the  air,  and  2-t  of  its  weight. 

The  elder  M.  de  Saussure,  in  his  beautiful  Treatise 
upon  the  Hygrometer^  has  determined  the  weight  of  the 
water  contained  in  a  cubic  foot  of  air,  at  different  tempe- 
ratures, and  has  prepared  the  following  table  of  th« 
results. 

1* 


CHYMISTRY    APPLIED    TO    AGRICULTURE- 


Degrees  of  tlie 
hygrometer. 

Weiglit 
of  the  water  contained  in 
a    cubic     foot    of   air    at 
66°.2  Fahrenheit. 

Weight 
of  the  water  contained 
a    cubic    foot    of  air 
45°.9  Fahrenheit. 

in 

at 

Grains. 

Grains. 

10 

0.4592 

0.2545 

20 

1.0926 

0.6349 

30 

1.7940 

1.0833 

40 

2.5634 

1.5317 

50 

3.4852 

2.0947 

60 

4.6534 

2.7159 

70 

6.3651 

3.3731 

80 

8.0450 

4.0733 

90 

9.7250 

4.9198 

98 

11.0690 

5.6549 

**  Consequently,"  adds  M.  de  Saussure,  '*  I  do  not  think 
we  are  far  from  the  truth,  in  assigning  11  grains  of  water 
to  saturate  a  cubic  foot  of  air,  at  the  temperature  of  15° 
of  Reaumur,"  (z=:65°.75  Fahrenheit.)  "  The  solution  of 
these  11  grains  of  water  in  a  cubic  foot  of  air  at  the  tem- 
perature of  15°  Reaum.  (=  65°.75  F.)  increased  the  den- 
sity of  the  air  so  riiuch,  that  the  barometer,  which  before 
was  at  27  in.,  rose  to  27  in.  5 """' 79,411,  that  is  to  say, 
about  27  in.  6  lines ;  consequently,  the  density  of  the  air, 
or  its  volume  in  the  receiver,  was  increased  about  J^." 

When  the  temperature  of  the  air  is  diminished,  the 
aqueous  fluid  is  condensed,  and  appears  in  the  atmosphere 
in  the  form  o-f  vapor,  and  is  deposited  in  the  state  of  dew. 
The  moisture  of  the  night  air  from  this  cause,  during  the 
heat  of  summer,  restores  vegetation  from  that  state  of  lan- 
guor produced  by  the  too  great  warmth  of  the  day. 

Oxygen  and  azote  have  been  classed  among  the  simple 
bodies  ;  carbonic  acid  and  the  aqueous  fluid  among  the 
compound  bodies,  of  which  the  principal  constituents  are 
known,  and  which  can  be  formed  and  decomposed  at  will. 

27.36 
72.64 
hydrogen 
.  .  .  oxygen 

Oxygen    and    azote    constitute,   essentially,    the 
sphere  ;  since,  when  the  two  other  principles  are  separated 
from  it,  it  still  retains  nearly  all  its  characters  of  form, 


100  parts  of  carbonic  acid  contain  ; 
100  parts  of  water  contain 


carbon 
oxygen 


11.06 

88.94 
atmo- 


CHYMISTRY    APPLIED    TO    AGRICULTURE.  7 

elasticity,  &c.  It  however  loses  its  most  important  powers 
of  influencing  vegetation ;  so  that  all  the  substances  found 
in  the  atmosphere  are  necessary  to  the  production  and  re- 
newal of  the  phenomena  which  the  three  kingdoms  pre- 
sent to  us. 

Of  the  four  principles  of  which  I  have  just  spoken,  as 
constituting  the  atmosphere,  the  aqueous  fluid  is  that 
which  appears  to  be  the  least  closely  united  to  the  others ; 
since  a  change  of  temperature  alone  is  sufficient  to  pro- 
duce a  change  of  its  proportions ;  whilst  azote,  oxygen,  and 
carbonic  acid  preserve,  always,  nearly  the  same  relative 
proportions ;  nor  can  they  be  varied,  or  disunited;  by 
means  of  compression  or  change  of  temperature.  The 
aqueous  fluid  does  not  rise  to  a  great  height  in  the  atmo- 
sphere ;  for,  according  to  the  reports  of  those  experimental- 
ists who  have  arrived  at  their  conclusions  by  the  assis- 
tance of  air-balloons,  the  higher  regions  of  the  atmo- 
sphere are  very  dry,  so  as  to  produce,  by  the  avidity  with 
which  they  absorb  the  moisture  from  the  boat  of  the  bal- 
loon, a  warping  and  cracking  of  its  boards,  as  if  they  had 
been  exposed  to  a  strong  heat.  This  effect  is  produced 
by  the  dryness  of  the  atmosphere  and  the  diminution  of 
its  specific  gravity. 

The  manner  in  which  the  atmospheric  elements  are 
united  is  worthy  of  notice.  This  union  is  sufficiently 
strong  to  counterbalance  the  diflTerence  in  their  specific 
gravities,  and  not  to  allow  them  to  be  separated  by  com- 
pression, or  the  tumultuous  agitation  of  the  air ;  and  yet 
it  permits  the  various  principles  to  be  decomposed  and 
isolated,  by  presenting  to  them  bodies  for  which  they  have 
some  slight  affinity.  Thus,  if  we  inclose  under  a  bell- 
glass  any  volume  whatever  of  atmospheric  air,  the  aqueous 
fluid  may  be  extracted  from  it,  by  the  calcined  muriate  of 
lime.  The  combustion  of  phosphorus  in  it  will  absorb 
the  oxygen  gas ;  lime-water,  or  the  caustic  alkalies,  will 
combine  with  the  carbonic  acid  ;  and  nothing  will  remain 
but  azote,  which  is  the  portion  that  has  the  least  tendency 
to  form  combinations. 

This  weak  state  of  union  among  the  principles  con- 
tained in  the  atmosphere  is  necessary,  in  order  that  they 
may  exert  their  powerful  and  constant  action  upon  all  the 
various  bodies  which  cover  the  surface  of  the  globe  ; 
the  composition  and  decomposition  of  which  cannot  be 
effected  otherwise  than  by  the  means  of  these  agents. 


8  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Independently  of  those  bodies  which  essentially  consti- 
tute the  atmosphere,  there  are  mingled  in  it  the  exhala- 
tions constantly  arising  from  the  earth ;  these  are  again 
disengaged  from  the  air,  and  precipitated,  as  soon  as  the 
heat,  or  any  other  cause  which  occasioned  their  ascen- 
sion, ceases  to  act  upon  them.  These  exhalations  modify 
the  properties  of  the  air,  and  affect  its  purity.  The  oxy- 
gen and  the  water  of  the  atmosphere  become  impregnated 
with  the  particles  of  the  exhalations  which  are  deposited 
with  them  upon  the  surfaces  of  other  bodies,  where  they 
remain  in  contact,  or  enter  into  combination,  with  them. 
The  origin  and  dissemination  of  many  maladies  may  be 
traced  to  this  source ;  the  germ  of  them  is  carried 
through  the  air  by  the  aqueous  fluid.  And  for  the  same 
reason  it  is,  that  intermittent  fevers  are  endemic  in  those 
situations,  where  large  quantities  of  animal  or  vegetable 
matter  are  undergoing  decomposition,  as  upon  the  borders 
of  ponds  and  marshes ;  and  that  the  miasm,  which  arises 
from  numerous  animal  remains  in  a  state  of  decompo- 
sition, becomes  a  fruitful  source  of  disease.  It  is  for  the 
same  reason  also  dangerous,  under  some  circumstances, 
to  breathe  the  evening  air ;  the  aqueous  fluid  contained  in 
it  is  loaded  with  the  noxious  principles,  which  the  heat 
of  the  sun  during  the  day  had  caused  to  ascend  into  the 
atmosphere.  The  disagreeable  odor,  conveyed  to  us  in 
mists,  is  owing  to  the  power  of  the  aqueous  fluid  in  trans- 
mitting the  exhalations  arising  from  the  earth. 

The  manner  in  which  the  air  conveys  to  us  the  per- 
fume of  plants,  and  the  odor  which  it  contracts  from  the 
exhalations  of  bodies  in  a  state  of  decomposition,  indicate 
clearly  its  influence  in  producing  maladies,  and  still  more 
plainly  its  power  of  propagating  those  that  are  contagious. 


ARTICLE  II. 

Of  the  Imponderable  Fluids  contained  in  the  Atmosphere. 

Besides  the  ponderable  substances  which  constitute  the 
atmosphere,  and  those  which  are  found  in  it  accidentally, 
it  receives  some  imponderable  fluids,  of  which  the  effects 
are  less  known,  but  which  appear  to  play  an  important 
part  in  the  atmospheric  phenomena ;  of  this  number  is 
the  electric  fluid. 


CHYMISTRY   APPLIED    TO   AGRICULTURE.  9 

1.  Electricity  is  developed  by  friction,  and  transmitted 
by  simple  contact.  It  is  accumulated  in  bodies  when  they 
are  insulated  ;  and  it  is  communicated  in  the  same  man- 
ner as  heat,  when  bodies  which  are  non-electric  ap- 
proach those  which  are  electric. 

The  singular  properties  of  the  electric  fluid  contained 
in  the  atmosphere,  and  the  frequent  variations  which  it 
undergoes,  give  rise  to  numerous  phenomena,  for  which 
observation  and  experiment  enable  us  to  account.  When 
this  fluid  is  abundantly  diff*used  throughout  the  atmo- 
sphere, it  exercises  a  powerful  influence  over  vegetation, 
excites  the  action  of  oxygen,  and  determines  the  conden- 
sation of  the  aqueous  fluid.  Davy  has  observed  that  grain 
germinates  more  quickly  in  water  charged  with  positive 
electricity,  than  in  that  which  contains  the  opposite  prin- 
ciple ;  and  that  it  is  a  well  known  fact,  that  fermentation 
takes  place  most  rapidly  during  a  thunder-storm,  and 
that  a  liquid,  composed  of  a  variety  of  principles  not  very 
closely  united,  milk  for  instance,  is  decomposed,  and  be- 
comes acid  under  a  highly  electric  state  of  the  air. 

2.  Whatever  may  be  the  opinion  we  may  adopt,  as  to 
the  nature  of  the  principle  of  heat,  there  can  be  no  doubt 
that  there  exists  in  the  atmosphere,  and  in  all  terrestrial 
bodies,  an  imponderable  fluid,  unequally  imparted  to  them, 
and  which  renders  their  state  solid,  liquid,  or  gaseous, 
according  as  the  affinity,  existing  between  their  par- 
ticles and  the  fluid  of  heat,  is  more  or  less  strong.  It  is 
this  state  which  we   regard   as  the  natural   state  of  bodies. 

Exposed  to  an  equal  degree  of  atmospheric  tempera- 
ture, all  bodies,  in  their  natural  state,  are  penetrated  by 
unequal  quantities  of  the  fluid  of  heat ;  but  as  the  fluid  is 
in  combination  with  the  particles  of  the  bodies,  and  thus 
forms  one  of  their  constituent  principles,  it  does  not  de- 
velope  its  most  important  property,  which  is  that  of  heat ; 
and  in  this  state  it  has  been  agreed  to  call  it  caloric,  and 
it  only  takes  the  name  of  heat  when  it  is  free,  and  disen- 
gaged from  all  combination. 

Caloric,  interposed  between  the  molecules  of  bodies, 
tends  to  separate  them  from  each  other ;  and  when  accu- 
mulated beyond  its  natural  quantity,  the  excess  acts  as 
heat ;  changing  the  form  of  bodies,  and  causing  them  to 
pass  from  the  solid  to  the  liquid  state,  or  from  the  last  to 
that  of  vapor. 

Those  bodies  which  exist  naturally  in  a  gaseous  state, 


10  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

and  which  are  rendered  solid  by  being  brought  into  com- 
bination with  other  substances,  return  to  their  natural 
state  as  soon  as  a  sufficient  degree  of  heat  is  applied  to 
destroy  the  force  of  the  affinity  which  unites  them  to  their 
base.  But  those  which  are  not  originally  gaseous  in  their 
form,  under  the  influence  of  heat  pass  through  all  the 
degrees  intermediate  between  their  natural  state  and  that 
of  imperceptible  vapor  ;  and  return  to  the  concrete  state 
when  deprived  of  the  excess  of  heat  which  had  been  ap- 
plied to  them. 

Caloric  can  be  extracted  from  bodies  by  percussion  or 
compression,  in  the  same  manner  as  water  is  expressed 
from  a  substance  which  has  imbibed  it.  When  a  body  is 
deprived  of  its  caloric  by  either  of  these  means,  the  mole- 
cules composing  it  are  brought  closer  to  each  other,  and 
its  porosity,  and  consequently  its  volume,  diminished. 
The  act  of  striking  or  rubbing  hard  bodies  together, 
produces  the  same  effect ;  the  portion  of  caloric,  which  is 
in  either  case  set  free,  acts  as  heat. 

The  temperature  of  bodies  can  be  lowered,  or  elevated, 
by  placing  them  in  contact  with  other  bodies  more  or  less 
hot  than  themselves.  The  fluid  of  heat  will  pass  from 
one  to  the  other,  and  produce  an  equilibrium  in  their 
state,  according  to  their  respective  capacities  for  caloric, 
which  enable  them  to  absorb  unequal  quantities  of  it. 

All  bodies  in  their  natural  state  contain  a  determinate 
portion  of  caloric ;  but  when  their  density  undergoes  a 
change,  by  the  variations  of  temperature  to  which  they 
are  exposed,  they  lose  or  absorb  caloric,  in  proportion  to 
their  contraction  or  dilation.  The  gases,  which  become 
solid  by  entering  into  combinations,  the  vapors  which  are 
condensed,  the  solids  which  are  contracted,  impart  to  the 
air  a  portion  of  their  caloric,  which  becomes  heat ;  whilst 
all  these  bodies,  on  receiving  heat  from  the  air,  are 
dilated. 

The  phenomena  of  composition  and  decomposition, 
which  uninterruptedly  renew  the  surface  of  our  globe, 
give  rise  every  moment  to  the  emission  or  absorption  of 
caloric.  Two  substances,  entering  into  combination,  form 
a  compound  which  perhaps  requires  more  or  less  caloric 
than  is  contained  in  the  two  component  principles;  and 
then  either  heat  or  cold  is  necessarily  produced  during 
the  operation.  Those  gases,  which  become  solid  by  en- 
tering into  combination,  part  with  their  caloric  whilst  un- 


CHYMISTRY    APPLIED    TO    AGRICULTURE.  11 

dergoing  the  change,  and  thus  produce  heat.  In  combus- 
tion, where  oxygen  is  the  principal  agent,  there  is  a 
constant  disengagement  of  caloric,  because  that  gas,  in 
general,  forms  solid  or  liquid  compounds  with  combustible 
substances ;  and  it  gives  out  a  portion  of  the  caloric  which 
preserved  it  in  its  gaseous  state. 

These  principles  established,  we  can  easily  explain  a 
part  of  the  effects  produced  upon  vegetation  by  the  varia- 
tions of  temperature. 

The  changes  of  temperature,  experienced  by  the  atmo- 
sphere in  the  course  of  a  year,  are  so  great,  as  to  cause 
some  liquids  to  pass  alternately  either  to  the  solid  or  aeri- 
form state,  and  some  solid  bodies  to  become  liquid.  The 
natural  effect  of  heat  upon  these  bodies  is,  by  dilating 
them,  to  weaken  the  force  of  cohesion  which  unites  their 
molecules,  and,  by  facilitating  the  action  of  chymical 
affinity,  to  enable  them  to  enter  into  combination  with 
foreign  bodies.  Thus  heat  renders  the  juices  of  plants 
more  fluid,  and  facilitates  their  circulation  through  the 
cells  and  capillary  vessels ;  and,  by  giving  activity  to  the 
suckers  of  roots,  enables  them  to  draw  from  the  earth  the 
juices  necessary  for  their  nourishment. 

Above  a  certain  temperature,  heat,  by  promoting  evapo- 
ration, causes  the  juices  of  plants  to  become  thickened 
and  dried  in  their  organs,  and  thus  vegetation  is  arrested, 
and  life  suspended.  This  effect  always  takes  place  during 
great  heats,  when  neither  rain,  dew,  nor  irrigation  can 
sufficiently  repair  the  loss  occasioned  by  evaporation. 
This  effect  would  be  more  frequent,  if  provident  Na- 
ture did  not  employ  means  to  moderate  the  action  of  heat. 

The  first  of  these  means  is  the  transpiration  of  the  vege- 
tables themselves,  which  cannot  take  place  without  carry- 
ing off  a  large  portion  of  heat,  and  thus  preserving  the 
transpiring  body  at  a  temperature  below  that  of  the  air. 
The  second  means  is  found  in  the  organization  of  leaves, 
which  are  the  only  parts  of  a  plant  where  transpiration 
takes  place.  That  surface  of  leaves  which  is  exposed  to 
the  direct  rays  of  the  sun  is  covered  by  a  thick  epidermis, 
which  resists  the  calorific  rays.  In  herbaceous  plants,  as 
in  the  stalks  of  grasses,  this  covering  is  composed  princi- 
pally of  silex.  In  other  plants  it  is  analogous  to  resin, 
wax,  gum,  or  honey  ;  whilst  the  epidermis,  which  covers 
the  opposite  sides  of  the  leaves,  is  fine  and  transparent. 


12  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

It  is  by  this,  that  transpiration  and  the  absorption  of 
nourishment  from  the  atmosphere  are  carried  on.  If  we 
should  reverse  the  order  of  things,  and  present  the  under 
surface  of  a  leaf  to  the  rays  of  the  sun,  we  should  very 
soon  see  that  it  would  make  great  efforts  to  resume  its 
natural  position. 

When  a  plant  is  dead,  or  rather  when  an  annual  plant 
has  fulfilled  its  destiny,  giving  assurance  of  its  reproduc- 
tion by  the  formation  of  its  fruit,  the  action  of  heat  and  of 
the  other  chymical  agents  is  no  longer  modified  by  any  of 
the  causes  of  which  I  have  just  spoken,  and  the  plant  re- 
ceives their  impression  in  an  absolute  and  unmodified 
manner.  •  When  the  temperature  of  the  atmosphere  sinks 
below  a  certain  point,  the  fluids  in  plants  become  con- 
densed, the  movement  of  the  juices  is  retarded,  the 
activity  of  their  organs  languishes,  and  is  at  length  sus- 
pended, until  restored  by  the  return  of  heat.  The  action 
of  the  atmosphere  upon  plants,  when  deprived  of  its  due 
proportion  of  heat,  is  however  modified  by  the  emission 
or  disengagement  of  caloric,  which  is  always  given  out 
when  liquids  are  condensed,  or  solids  contracted;  and 
this  occasions  the  temperature  of  plants,  during  the  winter, 
to  be   always  a  little  higher  than  that  of  the  atmosphere. 

It  sometimes  happens  that  the  temperature  of  the  at- 
mosphere sinks  so  low,  as  to  produce  fatal  effects  upon 
plants  by  freezing  their  sap,  and  thus  occasioning  their 
death.  This  effect  does  not  always  depend  upon  the  in- 
tensity or  degree  of  cold  to  which  they  are  exposed,  but 
upon  particular  circumstances.  I  have  seen  olive  trees 
resist  a  temperature  of  22° .2  Fahrenheit,  and  perish  from 
that  of  28°. 6,  because  in  the  last  case  the  snow,  which 
had  collected  upon  the  branches  of  the  trees  during  a 
night,  was  dissolved  the  following  day  by  the  heat  of  the 
sun,  and  the  wet  tree  was  exposed  during  the  succeeding 
night  to  the  action  of  28°. 6.  There  is  nothing  more  dan- 
gerous for  corn  and  grasses,  than  those  frosts  which  follow 
immediately  after  a  thaw,  because  the  still  wet  plants,  not 
being  deeply  rooted  in  the  ground  pulverized  by  the  frost, 
have  no  means  of  defending  themselves  from  the  effects  of 
the  cold. 

3.  Sennebier  was  the  first  to  admit  that  the  influence  of 
light  was  hurtful  to  the  germination  of  seeds.  Ingen- 
houz  confirmed  this  opinion  by  actual  experiment;  but 
M.  de  Saussure,  who  caused  grains   to  germinate   under 


CHYMISTRY    APPLIED    TO    AGRICULTURE.  13 

Iwo  receivers,  the  one  opaque,  and  the  other  transparent, 
is  convinced  that  germination  took  place  in  both  cases  at 
the  same  time;  but  that  the  subsequent  vegetation  was 
more  rapid  and  vigorous  under  the  transparent,  than 
under  the  opaque  receiver.  It  is  easy  to  reconcile  these 
opinions  and  results,  though  apparently  so  contradictory, 
by  separating  the  action  of  heat  from  that  of  light.  As 
plants  transpire  very  little  during  their  first  stage  of  ger- 
mination, if  they  are  exposed  to  the  united  influence  of 
the  two  fluids,  that  of  heat  will  exercise  upon  them  its 
full  force,  because  there  is  no  evaporation  from  them  to 
temper  its  effects,  and  their  delicate  organs  will  be  with- 
ered and  dried  up.  It  is  for  this  reason  that  gardeners 
are  so  careful  to  shelter  their  nurseries  from  the  rays  of 
the  sun,  and  not  to  expose  their  plants,  till  by  the  devel- 
opement  of  their  leaves  they  are  able  to  moderate  the 
effects  of  heat  by  transpiration. 

Though  the  action  of  light  upon  vegetation  does  not 
appear  to  be  so  important  as  that  of  the  other  fluids  of 
which  I  have  spoken,  it  is  not  in  reality  less  so.  Plants, 
which  are  raised  in  the  shade  or  in  darkness,  are  nearly 
or  quite  without  color,  perfume,  taste,  or  the  firmness  of 
texture  of  those,  that  are  exposed  to  the  direct  rays  of  the 
sun  ;  and  if  the  luminous  fluid  does  not  combine  with  the 
organs  of  plants,  we  cannot  deny  that  it  is  a  powerful 
auxiliary  in  their  combinations. 

It  is  generally  acknowledged  that  plants  do'  not  emit 
oxygen  gas,  excepting  when  exposed  to  the  direct  rays  of 
the  sun  ;  and  it  is  known  also  that  flowers  rarely  produce 
fruit,  if  raised  entirely  in  the  shade.  According  to  the 
observations  of  M.  Decandolle,  the  sensitive  plant,  if  car- 
ried into  the  shade,  closes  its  leaves  as  during  the  night, 
and  reopens  them  immediately  upon  being  again  exposed 
to  the  rays  of  the  sun  or  of  a  lamp. 

The  grand  discoveries  of  Herschel  have  thrown  great 
light  upon  these  delicate  questions.  That  learned  philoso- 
pher has  proved,  that  amongst  the  various  rays  consti- 
tuting a  pencil  of  light,  there  are  some  that  possess  nearly 
exclusively  the  property  of  being  luminous,  others,  that  of 
affording  heat.  Wollaston  and  Ritter  have  added  to  these 
important  facts,  that  there  exists  a  third  species  of  rays, 
which  appear  to  act  upon  bodies  as  powerful  chymical 
agents. 

When  we  reflect  upon  the  influence  which  the  atmo- 
2 


14  CHYMISTRY    APPLIED    TO    AGRICULTiJRE. 

sphere  exercises  over  vegetation  and  over  the  principal 
qperations  which  are  carried  on  in  rural  establishments, 
such  as  fermentations,  the  preparation  of  various  produc- 
tions, and  the  decomposition  of  some  substances,  in  order 
to  apply  them  to  particular  purposes ;  we  are  astonished 
at  finding  nowhere  any  of  the  simple  and  unexpensive  in- 
struments which  announce  its  changes  every  moment. 

I  do  not  propose  that  delicate  or  complicated  instru- 
ments should  be  provided ;  but  I  wish  to  find  on  every 
farm  an  hygrometer,  to  ascertain  the  humidity  of  the  at- 
mosphere, a  thermometer  to  indicate  the  changes  of  tem- 
perature, and  a  barometer  to  determine  the  weight  of  the 
atmosphere.  This  last  instrument  would  be  particularly 
valuable,  as  predicting  the  changes  of  the  weather;  the 
rising  of  the  mercury  announces  the  return  of  dry  weather, 
and  its  sinking  warns  us  of  rain  and  storms.  We  can 
regard  these  variations  but  as  signs;  but  they  are  signs 
much  more  certain  than  those  which  country  people  de- 
rive from  the  changes  of  the  moon. 


CHAPTER  II. 

OF  .THE    NATURE  OF    EARTHS,  AND  THEIR   ACTION    UPON 
VEGETATION. 

Nearly  all  vegetables  derive  their  support  from  the 
earth.  There  are  however  some,  the  seeds  of  which,  be- 
ing deposited  upon  trees  by  birds  or  by  the  winds,  germi- 
nate and  grow,  appearing  to  be  in  the  situation  designed 
for  them  by  nature ;  such  are  the  mistletoe,  the  mosses, 
&/C.  There  are  others  that  float  upon  the  water,  or  fasten 
themselves  upon  dry  rocks,  upon  slates,  or  tiles ;  of  the 
last  kind  are  the  fleshy  plants.  As  the  earth  furnishes 
the  greatest  number  of  plants,  and  all  those  which  are  of 
the  most  importance  to  man,  its  influence  upon  vegetation 
is  of  the  greatest  consequence,  and  at  the  same  time  one 
of  the  most  diflficult  things  of  which  we  can  treat. 

Plants  are  not,  like  animals,  endowed  with  powers  of  lo- 
comotion ;  but  are  always  fixed  to  a  limited  portion  of  the 
soil.  They  depend  upon  the  small  space  which  they  oc- 
<jupy  for  the  supply  of  their  wants ;  they  can  place  under 
contribution  only  those   portions  of  the  surrounding   air, 


OF    MOULD.  15 

earth,  and  water  tliat  come  in  contact  with  them ;  it  is 
necessary,  then,  that  they  should  find  immediately  around 
them  the  nutritive  principles  requisite  for  their  growth, 
and  for  the  exercise  of  their  functions;  it  is  necessary 
that  they  should  be  able  to  extend  their  roots,  in  order  to 
draw  from  the  soil  its  nourishing  juices;  and  to  fasten 
themselves  in  the  earth,  so  as  to  be  secure  from  being 
dried  up  by  heat  or  uprooted  by  the  winds. 

As  all  the  qualities  required  by  a  vigorous  vegetation 
cannot  always  be  found  united  in  land  appropriated  to  cul- 
tivation, we  are  led  to  examine  the  nature  of  earths,  and 
the  differences  which  exist  amonir  them. 


ARTICLE  I. 

Of  Mould. 


All  plants,  when  dead,  are  more  or  less  readily  decom- 
posed ;  and  in  undergoing  these  changes,  which  are 
greatly  facilitated  by  air  and  heat,  they  form  products 
with  which  it  is  of  importance  for  us  to  be  acquainted  ; 
as  the  principal  aliments  of  living  plants  are  furnished  by 
those  that  are  dead.  Decomposition  is  most  rapid  in  suc- 
culent vegetables,  and  in  those  which  are  collected  in 
heaps ;  but  a  high  degree  of  atmospheric  temperature  and 
the  humidity  of  plants  contribute  powerfully  to  accelerate 
it.  During  decomposition  much  carbonic  acid  is  given 
out ;  a  part  of  this  exists  in  combination  with  the  constitu- 
ent principles  of  the  plant,  and  a  part  of  it  is  produced  by 
the  action  of  the  oxygen  of  the  atmosphere  upon  the  car- 
bon of  the  plant;  hydrogen,  which  is  probably  furnished 
by  the  decomposition  of  the  watery  particles,  and  is 
generally  carburetted,  is  likewise  exhaled,  as  also  am- 
moniacal  gas  when  its  elements  exist  in  the  plant; 
When  large  masses  of  vegetables  are  in  a  state  of  fermen- 
tation, heat  is  always  produced ;  but  if  they  have  been 
dried,  it  is  necessary  to  collect  them  into  heaps,  and 
moisten  them  slightly  in  order  to  determine  their  fermenta- 
tion and  decomposition ;  in  this  case  the  heat  produced 
is  sometimes  so  great  as  to  cause  the  combustion  of  the 
mass ;  a  phenomenon  which  occurs  when  hay  is  stacked 
without  being  sufficiently  dry,  or  when  ropes,  hemp,  or  flax 
are  piled  up  wet. 


16  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

When  all  the  parts  of  a  plant  are  decomposed,  there  i» 
produced  an  earthy  residuum  of  a  brown  color,  which  is 
called  mould.  In  this,  besides  the  salts  and  the  earths 
which  it  contains,  are  found  some  oils  and  extractive 
principles  which  escape  decomposition. 

The  distillation  of  mould  in  a  retort,  produces  much 
carburetted  hydrogen,  some  carbonic  acid,  a  bituminous 
empyreumatic  oil,  and  some  water  holding  in  solution 
pyroligneous  acid  and  carbonate  of  ammonia. 

The  analyses  by  fire  do  not  produce  any  substances, 
such  as  exist  in  vegetables  and  animals ;  they  decompose 
the  natural  products  of  the  plant,  and  present  their  ele- 
ments under  different  combinations.  The  analysis  of 
mould  by  washing  in  water,  leads  us  to  a  beiter  knowledge 
of  its  component  parts,  and  of  its  actions  upon  vegetation. 
M.  de  Saussure  found,  that  pure  mould,  formed  in  an  open 
field,  -leached  twelve  times  with  boiling  water,  yielded  a 
dry  extract  equal  to  y\-  of  its  weight;  rich  garden  soil, 
and  the  light  soft  earth  from  a  field  which  bore  a  good 
crop,  yielded  the  same  extract,  but  in  less  quantity.  This 
learned  philosopher  is  convinced,  that  the  excellence  of 
mould  does  not  depend  upon  the  proportion  of  the  ex- 
tractive matter  which  it  contains. 

Mould  furnishes  by  distillation  nearly  the  same  princi- 
ples after  being  deprived  of  its  extract  by  washing,  as 
before ;  but  its  powers  of  supporting  vegetation  are  less  in 
the  first  case,  than  in  the  second. 

When,  after  repeated  washings,  no  more  extract  can  be 
obtained  from  mould,  it  is  only  necessary  to  moisten  it, 
and  leave  it  exposed  to  the  air  for  three  months,  in  order  to 
have  it  yield  fresh  supplies.  These  macerations,  continued 
for  a  long  time  upon  the  same  mould,  have  always  produced 
colored  infusions,  approaching  in  their  qualities  to  the 
extract,  (Saussure,)  which  proves  that  new  combinations 
are  formed  by  the  successive  changes  of  vegetable  pro- 
ducts, and  that  the  result  of  these  combinations  is  soluble 
in  water,  after  it  appears  to  have  exhausted  its  solvent 
power  upon  the  bodies.  This  fact  is  the  more  important, 
as  it  shows  that  the  nutritive  quality  of  vegetable  manures 
may  continue  during  the  whole  time  of  their  decomposi- 
tion, because  they  form  new  products  soluble  in  water, 
which  will  afterwards  serve  as  nourishment  for  plants. 
This  fact  proves  still  farther,  that  some  substances, 
by   their   nature   insoluble  in  water,  may    form   excellent 


OF    iMOULD. 


17 


manures  during  the  various  stages  of  their  deconrpositions 
by  giving  rise  to  the  formation  of  products  very  somble. 

M.  de  Saussure  found,  that  mould  which  had  been  de- 
prived of  its  extract,  contained  a  little  more  carbon,  than 
that  which  had  not  been  so  deprived ;  the  former  yielded 
'331 ,  the  latter  31. 

One  hundred  parts  of  the  dry  extract  of  turf  mould 
furnished  14  parts  of  ashes,  which,  when  leached  with 
boiling  water,  afford  -^(^^  z=z  ^-^  of  salts  composed  of  pure 
potash,  muriates,  and  alkaline  sulphates. 

It  is  necessary  to  observe,  that  when  mould  is  reduced 
to  ashes,  the  action  which  water  exercises  upon  it  is  in 
inverse  proportion  to  the  power  of  the  heat  td  which  it 
has  been  subjected ;  if  that  have  been  very  intense,  a  sort 
of  semi-vitrification  takes  place,  which  unites  the  earthy 
principles  with  the  alkaline  salts,  and  renders  the  mass 
less  soluble  in  water.  M.  de  Saussure  has  proved,  that 
boiling  water  cannot  extract  at  most  more  than  y§^  =  ^^ 
of  the  salts  contained  in  the  ashes  of  mould  ;  whilst  after 
having  obtained  ^V  ^^  alkaline  salts  from  the  dry  extract 
of  mould,  by  the  aid  of  boiling  water,  he  procured  by 
another  analytical  process,  a  quantity  of  salts  equal  to  the 
first. 

With  the  exception  of  the  earthy  and  saline  principles 
contained  in  mould,  in  the  proportion  of  5  to  7,  all  the 
other  principles  are  entirely  destructible  by  the  action  of 
air  and  water. 

When  mould  is  exposed  to  the  action  of  air,  or  entirely 
immersed  in  water,  it  suffers  no  decomposition  ;  but  when 
it  is  brought  into  contact  with  the  atmosphere,  or  with 
oxygen  gas,  after  having  imbibed  water,  the  oxygen  com- 
bines with  the  carbon  of  the  mould,  and  produces  a  vol- 
ume of  carbonic  acid  gas,  always  equal  in  volume  to  the 
quantity  of  water  imbibed  ;  when  this  waiter  is  sufficiently 
impregnated  with  carbonic  acid,  the  volume  of  air  en- 
closed under  a  bell  glass,  in  contact  with  the  mould, 
suffers  no  further  change. 

The  carbon  of  which  the  mould  is  deprived  by  its  union 
with  oxygen,  is  not  in  proportion  to  the  loss  occasioned 
by  decomposition ;  it  still  disengages  carburetted  hydro- 
gen and  water,  which  proves  the  combination  of  oxygen 
with  hydrogen,  and  of  the  last  with  carbon.  The  decom- 
position of  mould  is  very  slow,  and  even  when  aided  by 
3* 


18  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

the  concurrence  of  air,  heat,  and  water,  is  completed  only 
at  the  end  of  some  years. 

Land  owes  its  fertility  mostly,  if  not  wholly,  to  the 
presence,  in  a  greater  or  less  abundance,  of  principles 
analogous  to  those  constituting  mould.  These  principles 
are  furnished  by  manures,  and  by  the  decomposition  of 
plants ;  but  each  harvest  causes  a  diminution  of  them,  a 
part  being  washed  away  by  rains,  and  a  part  absorbed  by 
the  crops  which  are  raised ;  thus  the  soil  is  deprived  by 
degrees  of  its  nutritive  qualities,*  till  at  length  nothing  re- 
mains but  an  earthy  residuum,  deprived  of  its  nourishing 
juices,  and  completely  barren  ;  it  is  to  restore  its  fertility 
that  land  must  be  manured  afresh,  after  having  yielded 
several  crops. 


ARTICLE  IL 

Of  the  Nature  of  Soils. 

The  question  which  we  are  now  about  to  treat,  is  one 
of  the  most  difficult  in  agriculture,  but  as  it  is  perhaps 
one  of  the  most  important,  we  ought  to  give  it  the  greatest 
attention,  and  to  direct  all  our  researches  to  proving  the 
difference  existing  amongst  arable  lands,  and  their  various 
properties. 

The  earth  furnishes  support  to  nearly  all  plants  ;  and 
as  each  species  of  these  requires  a  soil  suited  to  its  par- 
ticular organs,  we  find  that  different  portions  of  the  earth 
differ  widely  amongst  themselves  in  character.  An  ac- 
quaintance with  the  nature  of  soils  is  especially  necessary, 
as  it  serves  to  throw  light  upon  the  cultivation  of  vegeta- 
bles, which  are  principally  nourished  by  them,  and  upon 
the  suitable  adaptation  of  which  most  of  their  properties 
depend. 

Arable  soils,  which  are  the  only  ones  of  which  I  shall 
here  speak,  are  generally  composed  of  silica,  lime,  alumi- 
na, magnesia,  oxide  of  iron,  and  some  saline  substances. 
The  various  characters  of  soils  arise  from  the  different 
proportions  in  which  their  component  parts  are  combined ; 
and  the  name  given  to  each  is  according  to  that  of  the  pre- 
dominating portion  of  earth  found  in  it,  as  siliceous,  cal- 
careous, argillaceous,  &c.     It  is  necessary  that  they  should 


FORMATION  OF  ARABLE  LANDS. 


19 


be  classed  according  to  their  nature,  that  the  degree  of 
fertility  of  each,  and  the  kind  of  cultivation  to  which  it  is 
best  suited,  may  be  known. 

Not  one  of  these  earths  is  by  itself  well  adapted  to  cul- 
tivation, but  by  their  mixture  they  correct  the  qualities,  or 
supply  the  deficiencies  of  each  other  ;  the  best  soil  is  that 
which  unites  the  greatest  number  of  the  properties  most 
suited  to  vegetation. 

There  are  few  soils  that  do  not  contain,  in  addition  to 
the  above  mentioned  earthy  and  saline  principles,  some 
portion  of  substances,  resulting  from  the  decomposition  of 
animal  and  vegetable  matter,  by  which,  other  circum- 
stances being  the  same,  their  fertility  is  very  considerably 
influenced. 


ARTICLE   III. 

Of  the  Formation  of  Arable  Lands. 

Arable  lands  are  almost  entirely  produced  by  the  de- 
composition, from  various  causes,  of  the  rocks  which  form 
the  basis  of  our  globe.  The  water,  which  flows  in  tor- 
rents from  the  tops  of  the  mountains,  abrades  their  sides, 
and  detaches  from  them  large  portions  of  rock,  which 
being  afterward  swept  by  the  force  of  the  current,  and 
constantly  dashed  and  rubbed  together,  have  at  length 
their  corners  and  edges  broken  off,  their  forms  rounded, 
their  surfaces  smoothed,  and  their  size  diminished,  till 
they  form,  successively,  pebbles,  gravel,  sand,  and  mineral 
slime. 

The  number  and  magnitude  of  the  stones  found  in  the 
beds  thus  deposited,  depend  upon  their  distance  from  the 
mountains  whence  they  have  been  brought,  upon  the 
harder  or  softer  character  of  the  rock  whence  they  have 
been  broken,  and  upon  the  force  of  the  currents  by  which 
they  have  been  acted  upon. 

Nearly  all  the  lands  of  our  rich  valleys  owe  their  origin 
to  the  decomposition  of  rocks,  and  we  can  judge  of  the 
nature  of  the  principles  which  compose  them,  by  knowing 
those  of  the  mountains  whence  they  have  been  brought. 
The  deposits  from  granitic  mountains,  consisting  of  quartz, 
feldspar,  and  mica,  form  soils  mixed  with  silica,  alumina, 


20  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

lime,  magnesia,  and  oxide  of  iron:  Those  from  moun- 
tains of  the  quartzeous  formation  are  composed,  almost 
entirely,  of  siliceous  earth,  and  give  rise  to  soils  of  an 
analogous  character  ;  and  so  on  of  the  rest. 

It  would,  however,  be  erroneous  to  suppose  that  the 
lands  formed  by  the  waste  of  mountains  are  throughout 
of  the  same  nature,  or  contain  the  same  principles,  in  the 
same  proportions,  as  the  rocks  from  which  they  have  been 
produced^  Upon  this  supposition  it  would  be  necessary 
that  all  the  substances,  originally  contained  in  any  one 
kind  of  rock,  should  be  of  equal  specific  gravity,  and  pos- 
sess an  equal  affinity  for  water ;  and  this  is  not  the  case. 
Those,  the  particles  of  which  are  held  in  the  closest 
union,  are  deposited  first,  whilst  the  others  are  carried  on 
by  the  current ;  silica,  and  the  oxides  of  iron,  predominate 
in  those  which  are  first  deposited  ;  then  lime,  alumina,  and 
magnesia. 

It  is  very  interesting  to  trace  the  changes  which  take 
place  in  alluvial  soils,  according  to  their  distance  from  the 
rivers  which  brought  them ;  whether  we  consider,  in  these 
changes,  the  division  and  mixture  of  the  constituent  prin- 
ciples, or  the  varieties  which  they  present  at  different  dis- 
tances from  the  sources  of  their  origin. 

Independently  of  the  various  degrees  of  specific  gravity 
and  hardness  which  exist  amongst  the  earthy  principles, 
there  are  other  causes  which  contribute  powerfully  to  affect 
the  nature  of  alluvial  lands.  Rivers  receive,  in  their 
courses,  many  tributary  streams,  which,  mingling  the  frag- 
ments that  they  carry  with  the  spoils  of  the  others, 
modify  to  an  illimitable  extent  the  soils  which  they  pro- 
duce. It  frequently  happens,  that  this  mixture  of  the  mud 
of  two  rivers,  produces  a  soil  more  fertile,  than  would 
have  been  formed  by  either  of  them  singly  ;  the  qualities 
of  one  serving  to  correct  the  deficiencies  of  the  other. 
Thus  the  washings  from  moutnains  of  the  quartzeous  form- 
ation, combined  with  the  argillaceous  and  calcareous  por- 
tions of  the  wrecks  of  other  mountains,  constitute  a  more 
productive  soil  than  would  be  furnished  by  either  sepa- 
rately. 

The  greatest  part  of  those  lands  now  appropriated  to 
the  richest  culture,  are  but  the  ruins  of  those  imposing 
mountains,  the  sides  of  which,  rent  away  and  carried  off 
by  torrents,  are  in  their  passage  reduced  to  dust,  and  de- 
posited in  the  valleys  to  form  the  basis  for  agriculture. 


FORMATION  OF  ARABLE  LANDS.  21 

It  is  not  possible  to  refer  to  any  other  causes  than  those 
I  have  just  pointed  out,  the  formation  of  the  arable  lands 
of  the  valleys ;  those  which  are  found  upon  the  vast  table 
lands,  which  crown  the  tops  of  mountains  or  extend  along 
their  sides,  must  have  had  some  other  origin.  The  con- 
stant action  of  air  and  water,  alone,  might  have  produced 
the  plains,  but  so  gradually,  that  their  effects  would  only 
be  perceptible  after  a  lapse  of  many  ages,  if  other  agents 
did  not  conspire  with  them  to  hasten  the  decomposition  of 
the  rocks,  and  to  convert  them  into  arable  land. 

The  decomposition  of  such  rocks,  as  are  by  their  want 
of  density  permeable  by  water,  must  be  much  more  rapid 
than  that  of  those,  in  which  the  particles  are  more  closely 
united ;  and  rocks,  of  which  the  constituent  principles  pos- 
sess some  affinity  for  air  and  water,  will  yield  much  more 
readily  to  their  action,  than  those  in  which  no  such  affinity 
exists. 

In  order  to  account  for  the  action  of  air  and  water,  upon 
rocks,  it  is  necessary  to  consider,  that  many  among  them 
contain  lime,  very  imperfectly  saturated,  and  usually  some 
oxide  of  iron,  at  its  lowest  state  of  oxidation ;  the  lime  is 
constantly  disposed  to  imbibe  from  the  atmosphere  its  car- 
bonic acid,  whilst  the  oxide  of  iron  combines  with  its  oxy-  ^ 
gen ;  th«6e  combinations  will  be  very  rapid,  if  neither  the 
lime  nor  the  oxide  of  iron  is  united  to  any  other  sub- 
stances, which,  not  possessing  the  same  affinities  for  the 
constituents  of  the  atmosphere,  oppose  its  action  upon 
them. 

Rocks  are  frequently  moistened  by  water  for  a  consid- 
erable length  of  time,  without  being  much  affected  by  it ; 
but  when  it  has  at  length  insinuated  itself  into  their  pores, 
and  become  there  converted  into  ice  by  the  cold,  it  de- 
stroys by  its  expansion  the  cohesion  of  their  particles,  pro- 
ducing rents  and  fissures,  and  thus  giving  access  to  the 
air,  which  combines  with  the  lime  and  oxide  of  iron,  and 
produces  an  immediate  change  in  all  the  surfaces  exposed 
to  its  action  ;  from  this  moment  the  process  of  decompo- 
sition goes  on  more  rapidly  than  before.  The  lichens  and 
mosses,  which  fasten  themselves  upon  the  surfaces  of  rocks, 
continue  and  increase  the  change  ;  their  delicate  roots  are 
constantly  enlarging  the  crevices  caused  by  the  water,  by 
the  effort  they  make  to  insinuate  themselves  into  them  ; 
and  by  their  decay  they  afford  light  successive  layers  of 
pulverized  vegetable  matter. 


33  CHYMISTRY   APPLIED    TO    AGRICULTURE. 

Water,  by  its  own  action,  will  penetrate  by  degrees  into 
the  earthy  principles  of  rocks,  and  produce,  at  length,  the 
effect  mentioned  above  ;  but  its  power  is  wonderfully  in- 
creased, whilst  passing  from  its  liquid  state,  to  that  of  ice. 

As  soon  as  the  surface  of  a  rock  is  furrowed,  and  the 
mosses  and  lichens  have  fastened  themselves  upon  it,  all 
the  plants  which  require  but  little  nourishment,  take  root 
and  decay  there  in  turn ;  and  the  product  of  each  succes- 
sive decomposition  adds  something  to  the  slight  bed  of 
earth  formed  by  the  first,  till  in  time  a  soil  is  produced, 
fit  for  cultivation. 

Hitherto  we  have  considered  only  those  circumstances 
which  explain  to  us  the  formation  of  arable  lands ;  these 
causes  have,  without  doubt,  placed  at  our  disposal  all  the 
lands  which  are  appropriated  to  agriculture ;  but  the  hand 
of  man  and  the  successive  generations  of  plants  have 
rendered  them  still  better  suited  to  this  purpose. 

The  great  stones  which  injured  the  harvests  upon  allu- 
vial soils,  have  been  removed  by  blasting.  The  soils 
which  were  too  stiff  have  been  improved  by  a  suitable 
admixture  of  other  earths ;  all  the  soils  have  been  in  turn 
manured  by  the  remains  of  plants,  or  the  collections  of 
the  barn-yard ;  and  man  has  learned  by  experience  what 
kind  of  culture,  and  what  species  of  plants  are  siiited  to 
each  soil.  Nature  has  prepared  the  materials,  man  dispo- 
ses of  them  in  such  a  manner  as  to  cause  them  to  produce 
according  to  his  necessities,  or  his  tastes. 

But  in  what  does  the  difference  of  soils  consist?  and 
which  are  those  best  suited  to  agriculture  1 

In  examining  the  nature  and  variety  of  the  rocks,  of 
which  all  arable  lands  were  originally  but  the  ruins  ;  and 
which,  notwithstanding  all  the  labor  of  man,  preserve  their 
primitive  characters,  we  shall  find  the  following  varieties. 

Amongst  rocks  of  the  first  formation,  or,  as  they  are  call- 
ed, primitive  rocks,  granite  holds  the  first  rank  ;  it  is  gene- 
rally formed  by  the  aggregation,  more  or  less  compact,  of 
several  stones,  differing  among  themselves  in  form,  color, 
hardness,  and  composition ;  these  stones  are,  most  com- 
monly, feldspar,  quartz,  and  mica.  These  elements  of 
granite,  also,  separately  form  rocks,  in  which  only  two 
of  them  are  combined,  as  in  micaceous  schist,  which  is 
composed  of  quartz  and  mica,  disposed  in  beds,  sometimes 
curvilinear ;  quartz  forms  by  itself,  nearly  without  mix- 
ture, some  of  the  primitive  mountains. 


FORMATION  OP  ARABLE  LANDS.  SGS 

I  shall  confine  myself  to  these  two  species  of  rock,  be- 
cause the  others  are  not  so  widely  extended  over  the  globe, 
nor  do  they  present  themselves  in  as  large  masses  as  these. 
Neither  shall  I  speak  of  some  substances  that  are  found, 
more  or  less,  in  granite,  as  hornblende,  amphibole,  serpen- 
tine, &c.,  as  these  bodies  are  only  secondary  there. 

The  composition  of  the  various  stones  which  constitute 
granite,  is  widely  different ;  quartz  is  almost  entirely 
formed  of  siliceous  earth  ;  feldspar  of  silex,  alumina,  lime, 
potash,  and  the  oxide  of  iron  ;  mica  contains  besides  these, 
magnesia.  So  that  when  granite  is  decomposed,  it  produ- 
ces those  lands  which,  upon  analysis,  afford  all  these  prin- 
ciples; whilst  the  washings  from  the  quartz  mountains 
form  only  beds  of  siliceous  earth ;  and  the  ruins  of  rocks 
of  micaceous  schist  contain  only  the  elements  of  feldspar 
and  mica. 

The  calcareous  mountains,  composed  of  carbonate  of 
lime,  without  any  appearance  of  the  remains  of  organized 
bodies,  are  ranged  by  naturalists  amongst  primitive  rocks, 
and  give  rise  to  the  formation  of  calcareous  soils. 

All  the  lands  which  are  produced  by  the  destruction  of 
primitive  rocks  are  of  the  first  formation,  and  ought  to  be 
so  designated  to  distinguish  them  from  those  which  owe 
their  existence  to  other  causes,  of  which  I  am  now 
about  to  speak. 

Independently  of  those  causes  which  1  have  just  ex- 
plained, and  which  have  produced  the  formation  of  the 
greater  part  of  the  arable  lands,  there  are  others  to  which 
some  lands  owe  their  origin.  The  successive  destructions 
which  the  whole  surface  of  the  globe  appears  to  have  suf- 
fered ;  the  decomposition  of  pyritous  beds,  which  appear 
to  have  covered  a  part  of  it ;  the  numerous  lakes  which 
have  disappeared  by  the  hand  of  man,  or  by  the  acciden- 
tal rupture  of  their  natural  confines ;  the  eruption  of  vol- 
canoes ;  the  overflowings  of  the  sea  ;  the  bony  remains  of 
animals,  and  the  decay  of  vegetables  buried  in  the  ground, 
have  formed  soils  of  all  characters ;  and  these  have  after- 
wards been  applied  by  man  to  his  own  use. 


24?  CHYMISTRY   APPLIED   TO   AGRICULTURE. 

ARTICLE  IV. 

Of  the  Composition  of  Arable  Lands. 

It  would  be  easy  to  ascertain  the  nature  of  any  portion 
of  arable  land,  if  we  had  to  consider  only  the  character  of 
the  rock  from  which  it  was  produced ;  but  vegetation, 
time,  and  the  labor  of  man,  have  wrought  so  many  changes 
in  it,  that  the  primitive  character  has  nearly  disappeared; 
and  it  is  necessary  to  judge  of,  and  appreciate  it  in  its 
actual  state.  Still,  the  lands  devoted  to  agriculture  are 
generally  composed  of  silex,  lime,  and  alumina :  with 
these  are  intermixed  pebbles  or  sand  of  different  natures, 
and  in  vsCrious  proportions,  and  the  remains  of  animal  and 
vegetable  matter,  more  or  less  thoroughly  decomposed. 
The  other  substances  which,  by  analysis,  are  found  in 
these  soils,  are  not  in  sufficient  quantities  to  be  classed 
amongst  their  elements;  when  these  are  too  abundant, 
as  is  the  case  in  certain  localities  with  magnesia  and  the 
oxide  of  iron,  the  soil  becomes  less  fit  for  vegetation. 

The  best  basis  for  good  lands  is  a  mixture  of  lime, 
silica,  and  alumina ;  but,  in  order  that  they  may  possess 
all  the  desirable  qualities,  it  is  necessary  that  certain  pro- 
portions, which  an  analysis  of  the  best  lands  has  made 
known,  should  be  observed  in  the  mixture. 

I  propose,  in  the  first  place,  to  examine  in  what  propor- 
tions the  constituent  principles  enter  into  those  lands, 
which  are  the  most  favorable  to  vegetation,  and  afterwards 
to  ascertain  the  properties  peculiar  to  each  kind  of  soil ; 
and  to  enlighten  the  agriculturist  as  to  the  best  methods 
of  correcting  the  faults  of  one,  by  the  qualities  of  another. 
I  shall  then  treat  of  the  effect  produced  upon  the  fertility 
of  soils,  by  the  accidental  deposits  of  animal  and  vegeta- 
ble matter,  which  are  mingled  with  them;  and  I  shall 
conclude  by  a  short  exposition  of  the  means  which  can  be 
employed  by  the  agriculturist,  for  becoming  acquainted 
with  the  nature  of  his  lands. 

In  order  to  know  the  earthy  composition  of  those  soils, 
which  have  been  considered  the  most  fertile  in  various 
climates,  I  shall  have  recourse  to  the  analyses  of  them 
which  have  been  made  by  men  worthy  of  the  utmost  con- 
fidence^. 


FORMATION  t)F  ARABLE  LANDS.  25 

Bergmann  found  that  one  of  the  most  fertile  soils  in 
Sweden  contained 

Coarse  silex       ....  30  parts 

Silica 26 

Alumina 14 

Carbonate  of  lime   ...  30 

100 

Giobert  analyzed  a  portion  of  fertile  soil  from  the  neigh- 
bourhood of  Turin,  in  which  the  principal  earths  were  in 
the  following  proportions, 

Silica 77  to  79 

Alumina 9  to  14 

Carbonate  of  lime    .     .       5  to  12 
The  most  fertile  mixture  produced  by  Tillet,  in  a  great 
number  of  experiments  which  he  made  at  Paris,  was  com- 
posed of  f  of  clay,  f  of  finely  pulverized  limestone,  and  |  of 
fiand.     Upon  reducing  these  to  their  elements,  we  find 

Coarse  silex 25 

Silica 21 

Alumina 16.5 

'  Carbonate  of  lime 37.5 

An  excellent  soil  for  wheat,  in  the  neighbourhood  of 
Drayton,  in  Middlesex,  gave  f  of  siliceous  sand ;  the  re- 
maining f  were  composed  of  three  earths  finely  divided, 
in  the  following  proportions. 

Carbonate  of  lime      ....     28 

Silica 32 

Alumina 39  * 

I  do  iK)t  speak  of  the  water,  nor  of  animal  and  vegetable 
remains  contained  in  the  soil,  and  which  enter  into  its 
composition  in  the  proportion  of  about  -^jj. 

I  have  myself  analyzed  a  very  fertile  soil  formed  by  th« 
alluvions  of  the  Loire,  at  a  distance  of  three  hundred  and 

[*  Davy  {AgricuUtcral  Chemistry,  p.  162,)  states  this  analysis 
thus,  Parts. 

Carbonate  of  lime 28 

Silica 32 

Alumina 29 

Animal  or  veffetable  matter  and  moisture  .        .11 

-Tb.] 
3 


26  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

seventy-five  miles  from  its  source,  and  found  it  composed 
of 

Siliceous  gravel 32 

Calcareous  gravel 11 

Silica 10 

Carbonate  of  lime  .     .     •     .     .  19 

Alumina 21 

Vegetable  remains 7 

The  analysis  of  a  soil  in  Touraine,  which  produced 
excellent  hemp,  gave  me  of 

Coarse  gravel 49 

Carbonate  of  lime      ....     25 

Silica 16 

Alumina 10 

From  the  results  of  these  analyses  we  find,  that  in  the 
best  earths  there  is  a  large  proportion  of  gravel,  which 
renders  the  soil  light  and  easily  worked,  and  facilitates 
the  passing  off  of  superabundant  rains.  In  consulting  the 
analysis  of  less  fertile  soils,  we  find  that  their  fertility 
diminishes  in  proportion  as  one  or  the  other  of  the  three 
principal  earths  predominates ;  and  becomes  almost  noth- 
ing in  those  which  possess  the  properties  of  but  one. 
The  mixture  of  earths  then  is  necessary  to  the  formation 
of  a  productive  soil ;  and  their  proportion  can  be  varied 
only  according  to  the  nature  of  the  climate,  and  the 
kind  of  plant  to  be  cultivated.  Siliceous  and  calcareous 
earths  may  form  a  larger  proportion  of  the  soil  in  moist, 
than  in  dry  countries,  and  alumina  may,  in  its  turn,  pre- 
dominate in  those  lands,  which,  from  their  declivity, 
suffer  the  water  to  flow  off  freely ;  but  a  mixture  of  the 
three  earths  can  alone  form  a  good  soil,  and  too  great  a 
disparity  in  their  proportions  materially  affects  the  char- 
acter of  it. 

The  constituent  parts  of  a  soil  have  a  constant  tenden- 
cy to  become  pulverized,  and  at  length,  by  frequent  tilling, 
by  the  action  of  salts,  manures,  and  frosts,  they  are  reduced 
to  so  fine  a  powder,  as  to  cease  to  be  productive.  Rain 
falling  upon  ground  in  this  state  renders  it  perfect  mud, 
which  when  exposed  to  heat  becomes  so  hard,  that  the  air 
cannot  penetrate  it,  nor  the  tender  fibres  of  plants  force 
their  way  through  it. 

Davy  has  observed,  that  all  soils  composed  of  ^  of  im- 
palpable matter  are  completely  barren.     The  use  of  barn- 


FORMATION  OF  ARABLE  LANDS.  27 

yard  manure  will  correct  for  a  short  time  only  this  state  of 
a  soil,  and  it  is  better  to  mix  with  it  the  sand,  and  coarse 
gravel,  which  are  necessary  to  restore  it  to  fertility. 

It  appears  that  the  three  earths,  which  form  the  basis  of 
the  most  fertile  soil,  enter  into  the  composition  of  plants ; 
Bergmann  has  proved  this  by  analysis  of  several  kinds  of 
grain;  and  Ruckert  by  the  results  of  his  experiments 
upon  a  variety  of  vegetable  productions,  in  a  way  to  put 
it  beyond  doubt.  About  100  parts  of  ashes  well 
leached,  and  consequently  disengaged  of  all  their  salts, 
yielded 

Silica.        Lime.      Alumina. 

Ashes  of  wheat     ...     48         37  15 

"     of  oats     ....  68        26  6 

"      of  barley     ...     69         16  15 

"      of  rye       ....  63         21  16 

"      of  potatoes       .     .       4         66  30 

"     of  red  clover     .     .  37        33  30 

All  soils  are  not  composed  of  the  mixture  of  the  three 
most  important  earths ;  some  of  them  are  formed  by  the 
union  of  two,  as  of  silica  with  alumina,  or  of  carbonate 
of  lime  with  alumina,  6i>c.,  and  we  occasionally  fmd  each 
one  of  them  combined  separately  with  quartzeous  or  cal- 
careous gravel,  forming  land  which  may  be  cultivated. 

It  is  seldom  that  the  soils  of  which  we  have  spoken  in 
the  preceding  paragraph,  are  composed  solely  of  the  two 
substances  referred  to;  but  these  so  far  exceed  in  impor- 
tance all  the  others  which  enter  into  the  mixture,  as  to  give 
a  character  to  the  whole,  which  the  latter  cannot  much 
affect. 

The  mixture  of  silex  with  alumina  forms  that  soil  called 
clayey,  argillaceous,  or  simply  clay.  The  properties  of 
the  alumina  predominate  in  all  clayey  soils,  which  are 
less  fertile  in  proportion  to  the  increased  quantity  of  it 
which  they  contain ;  when  it  equals  or  exceeds  one  half, 
they  are  only  fit  to  be  employed  as  the  basis  of  some  kinds 
of  earthen  ware ;  especially  if  the  other  moiety  consist  of 
silex  finely  pulverized. 

I  have  had  occasion  to  analyze  three  specimens  of  clay 
taken  from  three  fields  situated  upon  a  plain,  formed  at 
most  wholly  of  argillaceous  marl ;  the  first  afforded 

Silex  in  grains 17 

Alumina 47 

Silica 21 


28  CHYMISTRY    APPLIED    TO    AGRICtJLTURE, 

,    Carbonate  of  lime      ....     10 
Carbonate  of  magnesia    ...     3 

Oxide  of  iron 2 

The  second 

Silex  in  grains 22 

.       Silica 15 

Alumina 45 

Carbonate  of  lime      .     .     .     .     11 
Carbonate  of  magnesia     ...     4 

Oxide  of  iron 3 

The  third 

Silex  in  grains 19 

Silica 24 

Alumina 40 

Carbonate  of  lime      ....       9 
Carbonate  of  magnesia    ...     5 

Oxide  of  iron 3 

The  other  principles  were  the  remains  of  manures  part  y 
decomposed.  These  three  portions  of  soil  were  from  land 
which  produced  but  little.  The  water  which  stands  upon 
clayey  soils  is  always  turbid  and  whitish,  especially  when 
agitated  by  the  winds ;  heat  has  the  effect  of  chapping 
and  splitting  these  soils,  and  hardens  them  so,  as  to  ren- 
der them  nearly  impenetrable  to  the  plough ;  in  order  to 
give  them  fertility  it  is  necessary  to  employ  a  great  deal  of 
undecomposed  barn-yard  manure  and  litter ;  and  it  is 
advisable  to  sow,  in  the  spring,  crops  of  buck-wheat. 

The  soils  which  are  formed  of  the  waste,  or  from  the 
decomposition,  of  mountains  of  calcareous  free-stone,  or 
of  the  carbonate  of  lime,  whether  primitive  or  secondary, 
frequently  present  only  a  mixture  of  calcareous  sand,  of 
which  the  grains  are  united  by  a  carbonate  of  the  same 
nature.  These  earths  are  in  general  light,  porous,  and 
well  suited  to  many  kinds  of  cultivation,  especially  in 
rainy  climates,  provided  the  bed  be  of  sufficient  depth, 
and  formed  upon  a  basis  of  rock,  to  enable  it  to  retain 
the  quantity  of  water  required  by  the  wants  of  vegetation  ; 
they  are  well  adapted  to  the  cultivation  of  the  vine,  and  of 
sainfoin  ;  and  when  they  can  be  well  manured  will  produce 
good  crops  of  rye,  oats,  and  barley.  These  soils  have  re- 
ceived the  name  of  calcareous,  though  they  almost  always 
contain  other  principles,  because  the  properties  of  the 
carbonate  of  lime  predominate  so  much  over  those  of  the 
other  substances,  that  the  latter  are  hardly  perceived. 


FORMATION  OF  ARABLE  LANDS.  29 

The  mixture  of  alumina  and  lime  constitutes  another 
species  of  soil,  which  by  itself  is  but  little  productive, 
especially  if  alumina  constitutes  more  than  one  half  of  it ; 
but  it  is  used  with  great  advantage  in  improving  some 
other  kinds  of  land.  The  soil  formed  from  this  mixture 
is  called  marl,  or  a  marly  soil ;  the  nature  of  it  varies 
much,  according  to  the  difference  in  the  proportions  of  its 
constituent  principles ;  it  is  called  clayey,  or  fat,  when 
the  qualities  of  alumina  predominate  in  it,  and  calcareous, 
or  poor,  when  the  calcareous  sub-carbonate  gives  it  its 
character.  Marl  often  contains  shells,  whole  beds  of  it 
being  sometimes  formed  almost  entirely  of  their  ruins ;  the 
^'fahluns  "  *  are  of  this  species ;  this  is  the  poorest  kind, 
and  the  most  suitable  for  improving  argillaceous  soils. 
The  fat  marl  is  often  mingled  with  siliceous  sand,  which 
serves  to  enhance  its  value  when  used  in  amending  light 
and  calcareous  earths.  I  have  seen  marl  containing  /^ 
of  sand,  -fjP^  'of  alumina,  and  y\y^  of  carbonate  of  lime, 
used  with  advantage  upon  soils  purely  calcareous. 

Marl  is  usually  found  in  beds,  buried  at  a  slight  depth 
in  the  earth ;  when  taken  out  and  exposed  to  the  air  it 
presents  appearances  which  vary  according  to  its  quality. 
Under  the  combined  influence  of  air  and  water,  it  is 
generally  reduced  to  powder ;  but  the  decomposition  is 
much  more  speedy  and  complete,  when  the  two  earths  are 
in  their  proper  proportions,  than  when  either  of  them  pre- 
dominates. 

The  action  of  water  dissolves,  and  carries  off  the  alu- 
mina gradually,  the  carbonic  acid  of  the  atmosphere  com- 
bines with  the  lime,  which  remains  unsaturated,  whilst 
the  oxygen  acts  upon  the  iron,  increasing  its  oxidation, 
till  an  entire  change  is  produced  in  the  nature  of  the 
earth,  which  acquires  properties  before  strangers  to  it ;  it 
becomes  pulverulent,  and  it  is  in  this  state  that  it  is  used 
to  fertilize  other  earths. 

"When  marl  is  very  argillaceous,  it  may  be  hardened  by 
the  action  of  fire,  and  it  then  becomes  sonorous,  like  well 
baked  potter's  ware ;  when  it  is  very  calcareous,  fire  con- 
verts it  into  lime  ;  and  I  have  seen  it  in  Cevennes  forming 
an  excellent  mortar  when  combined  with  a  sufficient  quan- 
tity of  sand. 

There  is  an  immense  difference    in    the  proportions  ia 

£*  Probably  "  muschelkalk,"  or  variegated  marls. — ^Tr.] 


30  CHYMISTRT    APPLIED    TO    AGRICULTURE. 

which  the  two  earths  combine  to  form  marl.  Numerous 
analyses  have  been  made  by  me  of  the  marls  of  the  cen*- 
tre  and  south  of  France,  and  I  have  found  them  to  con- 
tain from  10  to  60  per  cent,  of  sub-carbonate  of  lime, 
from  15  to  50  of  alumina,  and  from  15  to  66  of  siliceous 
sand.  Marl  is  often  produced  by  the  decomposition  of 
silex  or  flint. 


ARTICLE    V. 

Of  the  Properties  of  the  different  Earths. 

As  the  several  earths  contained  in  the  soils  of  which  I 
have  just  spoken,  do  not  all  possess  the  same  qualities,  and 
are  very  differently  affected  by  air,  water,  and  heat,  the 
most  powerful  agents  of  vegetation,  the  excellence  of  a 
soil  depends  upon  its  containing  the  right  proportion  of 
each  species  of  earth  ;  and  that  is  supposed  to  be  the  best 
soil,  in  which  the  virtues  of  one  portion  of  its  constituent 
principles  correct  the  faults  or  defects  of  the  rest.  In 
order  to  produce  these  mixtures,  to  supply  the  deficiencies 
of  poor  soils,  and  to  be  able  to  render  them,  by  art,  suita- 
ble to  the  production  of  some  particular  article  of  cultiva- 
tion, it  is  necessary  to  know  the  particular  properties  of 
each  kind  of  earth ;  and  it  is  upon  this  subject  that  I  shall 
now  speak. 

Siliceous  earth,  or  silica,  exists  in  all  hard  primitive 
rocks,  and  forms  nearly  the  whole  of  quartzeous  moun- 
tains. In  order  to  obtain  it  in  its  greatest  degree  of  purity, 
it  is  fused  with  six  parts  of  potash  ;  it  is  then  dissolved  in 
water,  and  separated  from  the  alkali  by  muriatic  acid  ;  the 
solution  is  evaporated  to  dryness,  and  the  residuum  wash- 
ed in  water  affords  pure  silica.  In  this  state  silica  has 
the  appearance  of  a  white  impalpable  earth,  rough  to  the 
touch ;  when  thrown  into  water  it  sinks  with  extreme 
rapidity,  but  its  particles  have  no  tendency  to  uuite  into 
one  mass.  The  weight  of  silica  compared  to  that  of  water 
is  2.5  to  1.* 

[*  Silica  exists  pure  in  rock  crystal,  and  nearly  pure  in  flint.  It 
may  be  obtained  pure  by  heating  rock  crystal  to  redness,  quenching 
it  in  water,  and  reducing  it  to  a  fine  powder.    Fuse  1  part  of  this 


PROPERTIES    OP    DIFFERENT    EARTHS.  31 

The  only  acid  which  has  been  found  to  act  upon  silica 
is  the  fluoric,  and  this  will  disengage  it  from  glass,  of 
which  it  is  one  of  the  constituents.  Hot  alkaline  lixivia 
at;t  slightly  upon  it.  It  is  found  abundantly  in  plants, 
where  it  could  only  be  introduced  in  a  state  of  extreme 
division,  or  by  being  dissolved  in  some  alkali. 

This  earth  undergoes  no  change  from  the  action  of  fire 
or  air,  because  it  is  saturated  with  oxygen ;  according  to 
the  analysis  of  Davy  and  Berzelius,  it  is  composed  of  equal 
parts  of  oxygen,  and  of  a  basis  called  silicium. 

According  to  my  experiments,  this  earth,  though  dry 
and  impalpable,  absorbs  scarcely  -^  of  its  own  weight  of 
water,  and  permits  it  to  escape  by  evaporation  in  ^  of  the 
time  in  which  carbonate  of  lime,  equally  divided,  parts  with 
it ;  and  in  ^  of  the  time,  in  which  it  escapes  from  alumina 
in  the  same  state. 

All  the  compound  primitive  rocks  contain  alumina ;  in 
order  to  obtain  this  pure,  it  must  be  precipitated,  by  the 
carbonate  of  ammonia,  from  a  solution  of  alum,  of  which 
it  forms  the  basis ;  the  precipitate  must  be  washed,  and 
ignited,  and  the  residuum  is  perfectly  pure  alumina ;  it  is 
always  in  the  form  of  a  white  powder,  and  possesses  the 
following  characteristics. 

It  is  very  astringent.* 

Its  specific  gravity  is  from  2.2  to  2.3. 

It  is  hardened  by  fire,  and  undergoes,  by  the  action  of 
it,  a  change  which  destroys  its  solubility  in  water. 

It  absorbs  water  with  great  avidity,  not  being  saturated 
with  less  than  2.5  of  its  own  weight,  and  retains  it  very 
forcibly,  especially  when  that  which  softened  its  surface  is 
evaporated  ;  yielding  it  entirely  only  at  a  temperature  suf- 
ficiently high  to  produce  fusion. 

Alumina  saturated  with  water  forms  a  soft  paste,  smooth 
to  the  touch,  easily  moulded,  and  receiving  without  diffi- 
culty any  form  which  one  may  wish  to  give  it. 

According  to  the  analysis  of  Berzelius,  alumina  consists 
of  46.70  of  oxygen,  and  52.30  o(  aluminum. 

powder  with  .3  of  potassa  in  a  silver  crucible,  and  evaporate  to  dry- 
ness. Wash  the  mass  in  boiling  distilled  water,  upon  a  filter,  and  the 
white  substance  which  remains  is  pure  silica.t  Its  color  is  white ;  its 
specific  gravity  2.66.— Tr.] 

[*  Brande  {Manned  of  Chymistry)  says  it  is  tasteless. — Tr.] 

j;t  This  is  the  usual  process,  but  the  silica  always  retains  potassa,  and  the  earth  ob- 
tained by  simply  reducing  the  colorless  rock  crystal  to  powder  is  more  pure.  (Brande'i 
Mamud  of  Chemistry,  p.  235.)— Te.] 


32  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Lime  is  found  in  nearly  all  primitive  rocks,  and  forms 
the  basis  of  all  calcareous  mountains,  whether  primitive 
or  secondary. 

It  is  obtained  pure  by  calcining,  at  a  high  temperature, 
Iceland  spar,  primitive  marble,  etc.,  or  by  precipitation 
from  a  solution  of  them  in  an  acid.  Its  taste  is  acrid  and 
caustic.  It  absorbs  water  with  avidity,  and  with  a  hissing 
noise,  and  forms  with  it  a  hydrate,  or  a  paste  which  is  the 
basis  of  mortars.  Carbonic  acid,  for  which  it  has  a  strong 
affinity,  combines  with  it,  separating  it  gradually  from  the 
water,  which  evaporates.  Pure  lime  is  composed  of  28.09 
of  oxygen,  and  71.91  of  calcium. 

The  lime  which  is  found  in  lands  appropriated  to  agri- 
culture, is  in  the  state  of  a  carbonate,  and  possesses  char- 
acteristics very  different  from  those  of  its  pure  state.  Its 
specific  gravity  is  2.0.  The  pulverized  carbonate  absorbs 
0.8  of  its  own  weight  of  water,  and  retains  it  less  forcibly 
than  alumina  does. 

The  mixture  of  these  earths  has  the  general  character 
which  results  from  the  union  of  the  qualities,  which  each 
earth  brings  into  the  composition  of  the  soil ;  but  inde- 
pendently of  the  action  which  these  principles  exercise 
upon  each  other,  air,  water,  labor,  and  the  use  of  manure, 
produce  modifications  of  the  soil  which  it  is  important  for 
us  to  understand. 

It  is  my  intention  to  examine  the  influence  which  all 
these  agents  exercise  over  the  various  soils,  and  I  enter 
upon  the  discussion  with  the  more  interest,  because  it 
furnishes  to  the  agriculturist  reasons  for  the  methods  he 
has  pursued  ;  and  explains  to  him  many  phenomena  which 
he  has  observed,  but  for  which  he  could  not  account. 

We  have  already  seen  that  the  atmosphere  furnishes  to 
plants  two  of  their  constituent  principles ;  of  which  one 
(carbonic  acid)  contributes  to  their  support  by  the  carbon 
which  it  deposits  in  them,  whilst  the  other  (oxygen) 
takes  from  them  a  portion  of  carbon  ;  this  last  becomes 
again  the  principal  agent  in  the  decomposition  of  manures 
and  dead  vegetables  ;  but  the  action  of  air  is  not  confined 
to  the  performance  of  these  offices,  however  important 
they  may  be. 

The  air  may  be  considered  as  a  vehicle  constantly 
loaded  with  a  quantity  of  water  in  vapor,  of  which  the 
coolness  of  the  night  causes  it  to  deposit  a  part  upon  the 
earth.     The  surface  of  the  ground  and  the  leaves  of  plants 


PROPERTIES    OF    DIFFERENT    EARTHS.  33 

are  often  moist  in  the  morning ;  the  return  of  the  sun  and 
the  heat  of  the  day  evaporate  this  liquid,  to  be  deposited 
again  at  sunset,  and  during  the  night ;  thus  by  an  alternate 
movement,  determined  by  the  changes  in  the  temperature 
of  the  atmosphere  at  different  periods  of  the  twenty-four 
hours,  water  is  constantly  applied  to  plants,  to  preserve 
them  from  the  excess  of  heat,  which  would  wither,  and 
dry  up  their  organs. 

The  aqueous  vapors  suspended  in  the  air  begin  to  be 
condensed  and  precipitated  at  sunset,  and  with  them  is 
deposited  the  greatest  part  of  the  emanations  which  have 
arisen  from  the  earth  during  the  day  ;  these  exhalations, 
though  beneficial  to  vegetation,  are  almost  always  injurious 
to  man,  and  it  is  not  without  reason  that  he  fears  and 
shuns  the  night  damps.  In  southern  climates,  where  the 
heat  of  the  sun  is  more  intense,  and  rains  less  frequrnt 
than  in  northern,  vegetation  is  supported  by  the  dews, 
which  are  very  abundant.  In  order  that  the  dews  of  night 
may  produce  their  best  effects  upon  vegetation,  it  is  neces- 
sary that  the  soil  should  unite  certain  qualities,  which  it 
does  not  always  possess. 

When  the  soil  is  hard  and  compact,  and  forms  by  the  ' 
action  of  the  air  an  impenetrable  crust,  the  dew  is  deposit- 
ed upon  its  surface,  and  evaporated  by  the  rays  of  the 
sun,  without  having  moistened  the  roots  of  the  plants,  or 
softened  the  earth  around  them ;  so  that,  of  the  organs  that 
serve  to  convey  nourishment  to  the  plants,  the  leaves  are 
the  only  ones  benefited  by  the  dew,  while  the  roots,  which 
are  the  principal  vehicles  of  nutriment  when  the  plant  is 
fully  developed,  are  not  in  any  degree  benefited  by  it. 
It  is  necessary,  in  such  cases,  that  the  soil  should  be  soft- 
ened, lightened,  and  divided,  so  that  the  air  may  convey  v 
the  water  with  which  it  is  charged,  to  the  roots  of  the 
plants,  and  to  every  part  of  the  earth  surrounding  them, 
to  a  certain  depth  ;  then  the  plant  can  imbibe,  through  all 
its  pores,  the  reviving  moisture  ;  and  that  which  is  received 
by  its  roots  is  more  lasting  than  that  which  it  absorbs  in 
any  other  way,  because  the  roots  being  sheltered  from  the 
direct  rays  of  the  sun,  evaporation  takes  place  less  rapidly, 
and  the  moisture  is  retained,  whilst  the  leaves  are  speedily 
dried  by  the  heat.  Besides,  that  earth  which  is  most 
easily  affected  by  the  dews,  yields  most  readily  to  the 
action  of  roots,  whether  it  be  to  fix  the  plant  firmly  by 
their  extension,  or  to  draw  from  the  soil  its  nutritive  prop-  / 
erties.  -^ 


34  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

This  explains  in  a  natural  manner  the  origin  of  a  cus- 
tom observed  by  all  agriculturists,  and  of  which  all  ac- 
knowledge the  advantage.  When  vegetables,  such  as 
peas,  beans,  potatoes,  and  other  roots  are  sowed  in  fur- 
rows at  equal  distances  from  each  other,  the  soil  in  the 
intervals  is  hoed,  or  dug,  with  the  utmost  care,  and  thus 
rendered  light,  soft,  and  permeable  to  the  air,  whilst  at 
the  same  time  weeds,  which  would  be  hurtful  to  the  culti- 
vated plant  by  depriving  them  of  nourishment  afforded  by 
the  ground,  are  destroyed ;  and  the  soil  rendered  more  fit 
to  receive  the  rain,  and  convey  it  to  the  roots.  I  do  not 
deny  that  these  benefits  are  real,  but  I  hold  them  to  be 
secondary,  and  subordinate  to  the  advantage  derived  from 
opening  access  to  the  air,  and  permitting  it  to  deposit  its 
dews  upon  the  roots,  and  upon  the  earth  in  contact  with 
them. 

I  have  uniformly  observed  the  effect  of  this  method  to 
be  equally  speedy  and  favorable  in  the  cultivation  of  beet 
roots,  and  I  have  never  employed  any  other,  to  restore  their 
vegetation  to  its  freshness  when  it  becomes  yellowish,  and 
drooping ;  in  three  or  four  hours  it  will  become  of  a  beau- 
tiful green,  and  the  leaves  spread  themselves  out,  although 
no  rain  may  have  fallen  ;  and  this  often  when  the  soil  had 
not  contained  a  single  weed.  I  have  observed  the  same 
effect  produced  upon  the  other  culinary  roots. 

A  custom  which  is  universally  practised  in  the  south  of 
France,  attracted  my  attention  for  a  long  time,  without 
my  being  able  to  account  for  it.  In  that  country,  where 
it  hardly  ever  rains  during  the  summer,  the  foot  of  each 
setting  of  the  vine  is  laid  bare  by  digging  around  it  a  cir- 
cular trench,  deep,  and  wide  enough  to  contain  uncovered 
the  stump,  and  the  radicles  proceeding  from  it ;  and  the 
opening  is  speedily  covered  over  by  the  leaves  and  branch- 
es. It  is  evident  that  this  method  has  no  other  advantage 
than  that  of  facilitating  the  access  of  the  air  to  the  roots, 
that  it  may  deposit  there  the  dew  with  which  it  is  more 
abundantly  charged  than  in  cold  climates;  if  it  were  not 
thus,  this  practice  would  expose  the  vines  to  be  dried  up 
by  the  scorching  heat  of  the  sun. 

All  soils  have  not  the  same  affinity  for  water,  which  arises 
from  their  different  degrees  of  tenuity,  or  the  division  of 
their  particles,  and  from  the  nature  of  the  substances  which 
enter  into  their  composition.  In  general,  the  more  finely 
the  parts  of  a  soil  are  divided,  the  better  they  absorb 
water 


PROPERTIES    OP    DIFFERENT    EARTHS.  35 

The  absorbing  powers  possessed  by  the  elements  com- 
posing a  fertile  soil,  may  be  arranged  in  the  following 
order. 

Vegetable  substances. 

Animal  substances. 

Alumina. 

Carbonate  of  lime. 

Silica. 

Alumina,  and  those  soils  where  its  characteristics  pre- 
dominate, do  not  receive  the  moisture  from  the  atmosphere 
to  the  greatest  advantage;  they  retain  the  water,  which 
they  imbibe,  with  so  much  force,  that  the  plants  produced 
upon  them  suffer  as  much  from  drought  as  if  they  grew 
in  sand. 

The  light  porous  earths,  composed  of  sand,  carbonate 
of  lime,  silica,  and  decomposed  animal  and  vegetable  sub- 
stances, in  just  proportions,  are  the  best  for  absorbing  and 
retaining  moisture,  in  order  to  transmit  it,  with  regularity 
and  beneficial  effect,  to  the  plant. 

The  experiments  conducted  by  Davy  have  produced  re- 
sults of  great  importance  to  agriculture ;  he  has  compared 
the  energy  with  which  various  soils  absorb  humidity  from 
the  atmosphere,  and  has  uniformly  found,  that  the  most 
fertile  possessed  this  power  in  the  highest  degree ;  so  much 
so,  that  the  fertility  of  soils  might  be  estimated,  and  class- 
ed according  to  it. 

1,000  parts  of  a  celebrated  soil  from  Ormiston,  in  East- 
Lothian,  which  contained  more  than  half  its  weight  of 
finely  divided  matter,  of  which  11  parts  were  carbonate 
of  lime,  and  nine  parts  vegetable  matter,  when  dried  at  a 
temperature  of  212°  Fahr.,  gained  in  an  hour  by  exposure 
to  an  atmosphere  saturated  with  moisture  at  a  temperature 
of  62°,  18  grs.  in  weight. 

1,000  parts  of  a  very  fertile  soil,  formed  by  the  deposits 
of  the  river  Parret,  in  Somersetshire,  gained  16  grs. 

1,000  parts  of  a  soil  from  Mersey,  in  Essex  gained  13 
grs. 

1,000  grains  of  a  fine  sand  from  Essex  gained  11  grs. 

1 ,000  grains  of  a  coarse  sand  gained  only  8  grs. 

1,000  grains  of  the  soil  from  Bagshot-heath  gained  but 
3  grs. 

The  absorbing  power  of  a  soil  has  always  been  found 
to  be  in  proportion  to  its  fertility,  and  to  the  excellence  of 
its  situation. 


36  CHYMISTRY   APPLIED    TO   AGRICULTURE. 

It  is  of  the  utmost  importance  in  the  science  of  agri- 
culture, that  the  comparative  powers  of  the  various  soils 
for  absorbing  atmospheric  moisture,  and  the  degrees  of 
force  with  which  they  retain  it,  should  be  ascertained. 
The  means  necessary  to  be  employed  in  ascertaining  these 
capacities  of  soils,  are  in  the  power  of  every  cultivator  ; 
he  has  only  to  dry  thoroughly  the  same  weight  of  each 
soil  in  a  state  of  equal  division,  and  to  weigh  them  night 
and  morning  for  several  days,  and  he  will  be  able  to  form 
an  estimate  of  the  quantity  of  moisture  which  each  has 
imbibed  during  the  night.  In  order  to  obtain  these  results 
with  exactness,  it  is  necessary  that  the  assays  should  be 
made  upon  equal  weights  of  earth,  in  an  equal  state  of 
division,  equally  dried,  and  spread  in  layers  of  an  equal 
degree  of  thickness. 

From  the  statements  which  I  have  made,  it  is  easy  to 
be  perceived,  that  air  and  water  are  two  powerful  agents 
in  promoting  vegetation ;  they  act  upon  it  directly,  by 
furnishing  from  their  own  decomposition  nutritive  princi- 
ples ;  and  they  act  as  auxiliaries,  by  serving  as  vehicles 
for  the  conveyance  into  the  organs  of  plants  of  such  sub- 
stances as  are  necessary  for  their  support. 

But  though  the  plant  is  furnished  with  aliment  through 
these  agents,  it  is  heat  alone,  that,  by  animating  the  vege- 
table organs,  enables  it  to  elaborate  within  itself  the 
nourishment  which  it  receives.  The  effect  of  temperature 
is  perceptible  not  only  in  plants,  but  in  many  classes  of 
animals ;  nearly  all  insects  are  benumbed  by  the  cold, 
and  reanimated  by  the  heat. 

All  soils  are  not  equally  capable  of  receiving  and  retain- 
ing heat.  The  white  earths  are  warmed  with  difficulty; 
when  pipe  clay  or  aluminous  marl  predominates  in  a  soil,  it 
is  nearly  always  damp,  and  retains  but  little  heat.  White 
chalky  soils  require  much  heat  to  warm  them  ;  but  they 
part  with  their  heat  less  quickly  than  the  first,  whilst  col- 
ored earths  absorb  heat,  in  proportion  as  the  depth  of 
their  hue  increases  from  brown  to  black. 

Davy  has  remarked  that  a  black  soil  containing  nearly 
■^  of  vegetable  matter,  when  exposed  to  the  sun,  acquired 
in  one  hour  an  elevation  of  temperature  which  raised  the 
thermometer  from  65°  to  88°,  whilst  under  the  same  cir- 
cumstances, a  soil  whose  basis  was  chalk,  raised  it  only 
to  69  degrees.  When  the  black  earth  was  carried  into 
the  shade  at  the  temperature  of  62°,  the  thermometer  fell 


PROPERTIES    OF    DIFFERENT    EARTHS.  37 

15°  in  half  an  hour,  and  the  chalky  earth  lost  by  the  same 
exposure  4°. 

Equal  quantities  of  fertile  brown  soil,  and  of  sterile 
clay,  were  dried ;  and  their  temperature  raised  to  88° ;  upon 
being  then  exposed  to  air  at  the  temperature  of  57°,  the 
brown  scTil  lost,  in  the  space  of  half  an  hour,  9°,  and  the 
clay  6°  ;  moistened  clay  at  88°,  exposed  to  a  temperature 
of  55°,  fell  to  the  same  in  less  than  a  quarter  of  an  hour.* 

The  variations  of  temperature  in  soils  of  different  na- 
tures, with  their  several  degrees  of  affinity  for  heat,  and  of 
power  for  retaining  it,  deserve  the  attention  of  the  agri- 
culturist. The  only  instrument  necessary  for  conducting 
experiments  upon  this  subject,  is  a  good  thermometer ;  and 
by  the  aid  of  that  we  can  ascertain  the  kind  of  soil  suited 
to  any  one  species  of  plant,  since  all  do  not  require  the 
same  intensity,  nor  the  same  continuance  of  heat. 

The  different  degrees  of  heat  which  earths  imbibe  at 
the  same  temperature  is  known  to  most  agriculturists,  and 
many  of  them  turn  the  knowledge  to  advantage.  It  is 
customary  with  those  who  cultivate  the  table  lands  upon 
the  sides  of  the  Alps,  to  throw  black  earth  upon  the  snow, 
in  order  to  hasten  its  thawing,  that  they  may  commence 
their  cultivation  as  soon  as  the  sun  returns  to  them.  The 
same  means  are  employed  in  green-houses  and  orangeries  ; 
the  walls  are  blackened,  and  the  soot  spread  over  the  soil 
serves  to  concentrate  and  fix  the  heat,  to  such  a  degree, 
that  in  the  month  of  July,  upon  the  Cramont,  at  an  eleva- 
tion of  9077  feet,  where  the  temjjerature  was  at  43°,  M. 
Saussure  found  that  a  thermometer  which  was  placed  in  a 
box  lined  with  blackened  cork,  and  of  which  the  opening 
was  closed  by  three  glasses  placed  at  some  distance  from 
each  other,  rose  in  two  hours  from  38°  75'  to  99°  5(y. 

Independently  of  the  heat  which  the  atmosphere  com- 
municates to  the  soil,  and  of  the  modifications  wrought 
upon  it  by  the  color  of  the  constituent  principles,  it  is  in 
the  power  of  art  to  lessen  or  to  increase  the  temperature  of 
lands  at  will.  Animal  manures  develope  more  or  less 
heat,  according  to  their  nature,  and  their  state  of  fermen- 
tation ;  those  which  have  not  been  decomposed,  excite 
more  heat,  and  maintain  it  for  a  longer  time,  than  others. 

[*  See  Davy,  p.  179, 180.     Chaptal  has  reduced  his  degreeB  erro- 
neously, and  they  are  corrected  as  above  &om  Davy's  £gricuUural 
Chemistry. — Tr.] 
4 


38  CHYMISTRY    APPLIED    TO    AGRICULT0KE. 

The  excrement  of  the  sh^ep  and  horse  is  more  heating  ire 
its  action  than  that  of  cows  ;  the  black  or  brown  manures 
warm  the  soil  more  than  marl  or  chalk. 


ARTICLE  VI. 

€)f  the  Properties  of  Mixed  Eai^ths,  and  the  3fethod3  of 
rendering  them  capable  of  a  good  Cultivation. 

I  BELIEVE  that  I  have  sufficiently  explained  the  origin 
©f  soils,  their  composition,  and  their  influence  upon  vege- 
tation ;  whether  it  be  exerted  through  their  constituent 
principles,  or  by  the  effects  which  are  produced  upon 
them  by  air,  heat,  &lc.  ;  it  now  remains  for  me  to  speak 
of  some  circumstances  which  modify  soils,  and  with  which 
the  agriculturist  ought  to  be  acquainted. 

I  have  repeated  several  times  in  this  chapter,  and  in 
that  in  which  I  have  spoken  of  manures,  that  the  results 
of  the  decomposition  of  animal  and  vegetable  substances, 
concur  with  the  constituent  principles  of  air  and  water  to 
form  the  food  of  plants ;  I  have  remarked,  that  plants  be- 
ing immovable,  it  was  necessary  that  these  supplies  should 
be  presented  to  them,  and  in  a  state  which  would  admit  of 
their  being  readily  absorbed  by  the  fibres  of  the  plants ; 
to  these  observations  I  have  added,  that  heat  animates 
plants,  and  gives  to  their  organs  the  power  of  decompos- 
ing these  substances,  and,  from  the  elaboration  of  them, 
of  forming  all  the  products  of  vegetation. 

In  order  that  plants  should  derive  the  greatest  advantage 
from  their  means  of  support,  it  is  necessary,  that  their 
nourishment  should  be  supplied  to  them  in  proportion  to 
their  wants,  and  consequently,  that  the  decomposition 
which  the  greatest  part  of  these  aliments  must  undergo, 
should  neither  be  too  speedy  nor  too  moderate;  the  soil 
appears  to  be  the  principal  agent  in  producing  these  modi- 
fications, and  serves  to  regulate  th«  others ;  it  forms  a 
magazine,  in  which  are  deposited  nearly  all  the  aliments 
of  plants,  and  it  ought  to  possess  alJ  the  properties  requi- 
site for  supplying  the  wants  of  vegetation. 

The  characteristics  which  mark  each  one  of  the  earths 
which  constitute  a  soil,  concur  by  their  union  to  produce 
this  effect;  chalk   and   silica  retain   but   little  water,  but 


PROPERTIES    OF    MIXED    EARTHS.  39 

their  mixture  with  alumina  preserves  plants  from  suffering 
so  often  from  drought ;  without  the  presence  of  alumina, 
they  would  be  alternately  inundated,  and  dried  up.  Clay 
alone  does  not  permit  the  roots  of  plants  to  extend  them- 
selves, nor  allow  the  air  to  penetrate  to  them  ;  but  mixed 
with  silica,  carbonate  of  lime,  and  sand,  it  forms  a  porous 
soil,  which  possesses  these  properties.  Chalk  preserves 
animal  and  vegetable  substances  from  a  too  rapid  decom- 
position. Alumina  and  the  oils  combined  together  pro- 
duce a  saponaceous  mixture,  which  can  be  imbibed  by 
plants,  and  thus  furnishes  them  with  two  principles,  which 
separately  are  insoluble  in  water. 

The  composition  of  soils  varies  according  to  the  differ- 
ence in  climate,  otherwise  their  fertility  would  be  les-  * 
sened.  The  quantity  of  rain  that  falls  is  so  various,  that 
even  within  the  extent  of  France,  it  ranges,  according  to 
situation,  from  twenty  to  thirty,  and  according  to  Giobert, 
at  Turin,  to  thirty-four  inches.  There  are  some  countries 
where  the  atmosphere  is  almost  always  cloudy,  and  the  air 
laden  with  moisture  ;  whilst  there  are  others  in  which  the 
sun  is  not  obscured  for  six  months  together.  It  is  evident 
that  in  those  countries  where  the  air  is  uniformly  damp, 
and  in  those  where  rain  is  abundant,  the  soil  may  be,  with- 
out inconvenience,  more  calcareous  than  argillaceous ;  and 
that  the  best  soils  in  the  two  divisions  would  differ  very 
widely  as  to  the  proportions  in  which  their  several  earths 
would  be  combined. 

Soils  should  vary  according  to  the  nature  of  the  plants  « 
to  be  cultivated  in  them  ;  some  prefer  a  porous,  dry,  and 
arid  soil,  others  flourish  only  in  land  constantly  moist ; 
there  are  some  that  require  a  great  degree  of  heat,  others 
vegetate  in  the  midst  of  snows.  These  peculiar  tastes  of 
plants  ought  to  be  known  to  the  agriculturist,  that  he  may 
select  for  each  one  the  soil  best  adapted  to  it ;  or  change 
the  characters  of  those  he  possesses,  so  as  to  afford  to  each 
plant  the  soil  most  congenial  to  it. 

In  order  that  a  plant  should  flourish  in  a  soil,  it  is  not 
always  sufficient  that  the  earths  composing  it  are  of  the 
right  kind,  or  suitably  proportioned;  it  is  necessary  to 
unite  other  circumstances  which  are  not  always  to  be  met 
with ;  for  example,  the  arable  soils  which  are  based  upon 
rocks,  vary  considerably  in  depth ;  and  the  thickness  of 
the  bed  not  only  exerts  an  influence  upon  the  powers  of 
ye^getation,  but  determines  the  kind  of  plant  which  can  be 


40  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

cultivated  upon  it.  The  bed  of  earth  ought  to  be  from  10  to 
12  inches  in  depth  for  grain,  and  much  more  than  that  for 
clover  and  sainfoin;  for  trees  it  must  be  much  deeper 
than  for  these,  otherwise  their  roots,  running  but  little  be- 
low the  surface  of  the  ground,  will  extend  their  shoots  to 
a  great  distance,  and  thus  exhaust  the  strength  of  a  large 

•  portion  of  soil.  Trees  are  often  found  upon  the  sides  of 
mountains,  which  are  almost  entirely  devoid  of  a  covering 
of  earth,  but  in  this  case  the  chinks  and  crevices  of  the 
rocks  supply  the  place  of  earth,  or  rather  the  rocks  are  of 
so  spongy  and  porous  a  nature,  as  to  permit  the  roots  to 
penetrate  them.  In  the  Cevennes  and  Limousin  the 
most  beautiful  chestnuts  are  planted  upon  granite  and 
Tree-stone;  and  the  famous  vines  of  the  Hermitage  pros- 
per in  a  soil  of  granite  decomposed  at  the  surface. 

It  is  not  immaterial  of  what  substance  the  sub-stratum 
of  the  beds  of  earth  are  composed  ;  if  it  be  of  sand,  the 
soil  above  will  dry  more  quickly  than  if  it  were  of  marl  or 
clay.  A  bed  of  clay  under  one  of  sand  contributes  to  its 
fertility  by  retaining  the  water,  which  easily  filters 
through  the  last,  and  thus  preserving  its  humidity  ;  but  if 
the  water  collected  upon  the  clay  moisten  for  too  long  a 
time  the  roots  of  the  plants,  they  become  languishing.  I 
have  always  observed  that  roots  might  be  exposed  to  living 
and  flowing  water,  without  being  injured  by  it,  but  that 
stagnant  water  is  always  hurtful,  and,  for  the  most  part, 
destructive  to  them.      Agriculturists  have  learned  this  by 

•  experience,  and  hence  has  arisen  the  custom  of  draining 
their  fields  and  meadows.  In  lands  which  are  too  moist, 
a  good  effect  is  produced  by  forming  beds  of  flints,  or  peb- 
bles, upon  which  a  layer  of  mould  may  be  placed  ;  I  have 
seen  excellent  meadows  made  in  this  way,  upon  land  which 
had  never  before  produced  any  thing  but  rushes. 

A  clayey  or  marly  soil,  which  lies  upon  a  bed  of  calca- 
reous and  porous  rock,  is  more  fertile  than  one  which  rests 
upon  a  foundation  of  hard  rock,  impermeable  to  water ; 
the  reason  of  this  is  very  simple ;  in  the  first  case,  the  wa- 
ter filters  through  the  rock,  and  escapes  ;  in  the  second  it 
remains  stagnant,  rendering  pasty  a  soil  possessing  none 
of  the  requisites  for  vegetation. 

The  situation  of  land  causes  a  great  variety  in  its  fertili- 
ty, and  in  the  nature  of  its  productions  ;  lands  which  have  a 
southern  exposure  dry  more  quickly  than  those  lying  towards 


PROPERTIES  OP  MIXED  EARTHS.  41 

the  north,  but  vegetation  is  more  active  in  the  fi^st  than  in 
the  last,  and  the  quality  of  their  productions  superior. 

The  slope  of  lands  likewise  affects  their  fertility;  a 
piece  of  ground  which  lies  upon  a  declivity,  loses  water 
more  readily  than  one  which  is  horizontal,  and  vegetation 
is  less  strong  upon  it,  but  the  productions  are  of  a  better 
quality.  There  is  a  vast  difference  between  wines  made 
from  the  same  kind  of  grape,  raised  in  the  same  soil,  if 
one  be  the  production  of  the  harvest  upon  the  declivity  of 
a  hill,  and  the  other  of  the  plain  at  its  foot. 

Inclined  lands,  where  the  slope  is  rapid,  and  the  soil 
light  and  porous,  are  liable  to  the  evil  of  having  the  ma- 
nures, applied  to  them,  carried  off  by  heavy  rains ;  even  the 
soil  sometimes  experiences  the  same  fate,  and  the  surface 
becomes  furrowed^  by  ravines  laying  bare  the  rocky  foun- 
dation. This  frequently  happens  to  lands  cultivated  upon 
the  sides  of  mountains,  till  they  become  at  length  com- 
pletely barren ;  and  hence  we  must  conclude  that  it  is 
unwise  to  clear  up  the  declivities  of  mountains,  since  a 
temporary  advantage  reduces  the  land  to  a  long  period  of 
sterility. 

Soils  composed  of  the  same  earthy  principles,  combined 
in  the  same  proportions,  will  still  present  very  different 
results,  according  to  the  nature  and  quantity  of  the  salts 
which  they  contain.  I  have  made  known  those  which  are 
usually  found  in  plants,  and  which  for  this  reason  must  be 
regarded  as  suited  to  vegetation  ;  but  their  proportions  are 
limited,  and  if  they  are  too  abundant,  they  become  hurt- 
ful. The  salts  cannot  be  regarded  as  the  actual  food  of 
plants;  they  are  only  auxiliaries,  though  very  powerful 
ones,  to  tlieir  nutrition.  The  organs  of  vegetables  require 
exciting ;  and  heat  and  the  salts  act  upon  them  as  stimu- 
lants. The  salts  are  to  plants  what  spices  and  marine 
salts  are  to  man.  Independently  of  their  stimulating 
powers,  the  salts  exert  a  chymical  action  upon  the  aliments 
of  plants,  by  combining  with  them,  rendering  some  of  them 
soluble  in  water,  and  moderating  the  decomposition  of 
others;  and  thus  contributing  to  regulate  and  facilitate 
the  process  of  nutrition. 

Even  from  the  part  which  the  salts  perform,  it  is  evident 
that  they  ought  to  be  supplied  only  in  suitable  proportions ; 
if  they  are  too  abundant,  or  very  soluble  in  water,  they 
will  be  absorbed  by  the  organs  of  the  plants  in  such  a 
quantity  as  to  produce  irritation  and  dryness.  Thus  tht 
4* 


42  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

best  soil  may  be  stricken  with  barrenness  if  the  salts  be- 
come too  abundant  in  it. 

Thorough  ploughing  contributes  largely  to  the  fertility 
of  lands ;  but  in  order  that  it  may  produce  its  best  effects, 
it  is  necessary  to  have  regard  to  some  circumstances 
which  are  generally  but  too  little  attended  to. 

Ploughing  divides  and  softens  the  soil,  mixes  thorough- 
ly its  constituent  principles,  destroys  weeds,  and  disposes 
them  to  decay  ;  and  frees  the  ground  from  those  insects 
which  often  abound  in  it. 

The  ploughings  should  be  more  numerous,  and  con- 
ducted with  more  care,  upon  a  heavy  soil,  than  upon 
one  which  is  light  and  porous.  Clayey  soils  should  be 
ploughed  only  when  dry ;  when  they  have  imbibed  water 
they  form  a  soft  paste,  on  which  ploughing  has  no  other 
effect  than  to  trace  furrows  in  the  mud.  Sandy  and  cal- 
careous lands  may  be  ploughed  at  all  times.  Deep  plough- 
ings are  very  advantageous  to  lands  which  are  of  the  same 
nature  to  a  considerable  depth,  since,  in  addition  to  the 
good  effects  arising  from  the  operation  itself,  those  parts 
of  the  soil  which  have  become  impregnated  with  the 
manures,  that  the  rains  have  carried  down  below  the  sur- 
face, are  thrown  up  to  contribute  to  the  nourishment  of 
vegetation.  Deep  ploughings  are  likewise  useful  in  those 
lands  where  the  upper  layer,  being  of  too  clayey  and 
compact  a  nature,  rests  upon  a  bed  of  sand  or  carbonate 
of  lime,  which  by  this  operation  is  brought  to  the  surface 
and  mingled  with  the  upper  layer,  thus  rendering  it  more 
fertile  than  it  could  be  made  by  any  other  means.  An 
equally  good  result  is  obtained  from  deep  ploughing  in 
the  reverse  case,  that  is,  Vhen  a  soil,  too  sandy  or  calca- 
reous, rests  upon  an  argillaceous  bed. 

But  deep  tillage  does  not  belong  to  all  soils,  nor  is  it  of 
use  under  all  circumstances.  For  instance,  if  a  soil  is 
situated  upon  a  vein  of  earth  charged  with  black  oxide  of 
iron,  or  upon  a  bed  of  marl,  the  mixture  which  would  be 
produced  by  deep  tillage  would  reduce  the  land  to  almost 
entire  sterility  for  two  or  three  years.  I  have  myself  ex- 
perienced this  result,  and  I  speak  from  personal  knowl- 
edge. Near  a  forest  of  oaks  upon  one  of  my  estates,  the 
land,  which  had  been  cultivated,  was  of  an  argillaceous 
character  for  about  six  inches  in  depth  ;  under  this  lay 
a  bed  of  very  dark  brown  earth,  of  five  or  six  inches  in 
thickness,  and  composed  of  silex,  clay,  and  oxide  of  iron. 


PROPERTIES    OF    MIXED    EARTHS.  43 

I  caused  the  two  beds  to  be  broken  up  and  mixed  well 
together  with  the  spade.  The  first  year  the  harvest  from 
it  was  almost  nothing,  much  less  than  before,  though  it 
had  never  been  fertile.  The  second  year  it  was  a  little 
more  productive  ;  but  it  was  not  till  the  fifth  year  that  it 
recovered  its  usual  degree  of  fertility.  One  of  my  friends 
possessed  a  piece  of  ground  of  a  moderate  degree  of  pro- 
ductiveness. The  soil,  which  was  sandy  and  very  dry, 
was  much  improved  by  the  application  of  marl,  which  he 
allowed  to  decompose  upon  it  for  two  years  before  cultiva- 
tion. As  the  same  person  had  a  bed  of  marl  in  one  of  his 
fields  at  the  depth  of  a  foot,  I  advised  him  to  break  up  a 
piece  of  it,  twelve  or  fourteen  yards  square,  and  to  mix 
the  marl  with  the  upper  layer  of  earth,  in  a  proportion 
more  considerable  than  in  the  other  case.  The  portion  of 
the  field  thus  operated  upon  was  nearly  barren  for  two 
years,  after  which  it  was  more  decidedly  fertile  than 
before. 

These  two  cases  struck  me  very  strongly.  I  sought  for 
the  reason  of  the  changes,  and  believe  that  I  have  found 
it  in  the  nature  of  the  inferior  layer  of  the  earth  at  the 
time  of  being  mixed  with  the  upper  soil. 

In  the  first  case  the  oxide  of  iron,  which  colored  the 
bed  brown,  was  at  the  lowest  state  of  oxydation ;  but  at 
the  moment  that  it  was  brought  into  contact  with  the  at- 
mospheric air,  it  began  to  combine  with  new  portions  of 
oxygen,  and  the  earth  could  not  become  fertile  till  the 
iron  was  saturated.  The  progress  of  oxydation  entirely 
changed  the  color  of  the  soil ;  from  black  it  became  of  a 
deep  lively  yellow.  This  fact  may  admit  of  a  diiferent 
explanation.  Is  the  oxide  of  iron,  in  its  black  state,  de- 
structive to  vegetation?  Does  that  oxide,  which,  by  at- 
tracting the  oxygen  from  the  atmosphere,  decomposes  it, 
destroy  by  its  action  the  necessary  and  salutary  influence 
of  that  fluid  upon  plants  ?  These  are  questions  which  can 
only  be  answered  by  a  long  experience. 

In  the  second  case  the  cause  of  sterility  was  differ- 
ent, though  it  had  a  general  relation  to  that  of  the  first. 
Marl  is  principally  composed  of  sub-carbonate  of  lime  and 
alumina ;  the  proportions  in  which  these  are  combined 
constitute  all  its  varieties.  The  lime  contained  in  marl, 
as  it  is  taken  from  the  bed,  is  never  saturated  with  car- 
bonic acid ;  but  after  being  exposed  to  the  air,  it  becomes 
at  length   saturated   with   the   acid    it    receives    from   it, 


44  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

crumbles,  and  effloresces.  The  decomposition  of  marl 
may  be  hastened  by  frequently  turning  it,  so  as  to  allow 
the  air  free  access  to  the  lime  ;  and  this  method  is  gene- 
rally practised  by  those  who  employ  marl  as  a  manure. 
The  same  questions  may  be  proposed  in  regard  to  imper- 
fectly carbonated  lime,  as  to  the  oxide  of  iron. 

When  M.  Fellenberg  wished  to  verify  his  principles  of 
cultivation  upon  his  estate  of  Hofwyl,  he  had  his  land 
broken  up  to  the  depth  of  three  or  four  feet,  and  it  pro- 
duced nothing  till  the  end  of  two  or  three  years. 

These  facts,  and  many  others  which  I  could  cite,  prove 
that  it  is  necessary  for  earths,  in  order  to  possess  great 
fertilizing  powers,  to  be  saturated  with  all  the  principles 
which  they  can  imbibe  from  the  atmosphere.  Thus  those 
which,  by  the  depths  of  their  beds,  have  been  constantly 
eecluded  from  the  action  of  the  air,  will  require  to  be 
exposed  to  it  a  long  time  before  becoming  fertile.  Those 
who  are  engaged  in  agriculture  know  this  fact,  and  ex- 
press it  by  saying  that  the  air  deposits  its  fructifying  prin- 
ciples upon  the  earth.  They  use  the  expressions,  —  "The 
soil  is  not  made  enough ;  is  not  ripe  enough  ;  is  not  aired 
enough,"  &c.  This  understanding  of  the  subject  is  not 
very  exact,  but  sufficiently  so  to  direct  their  practice. 

When,  by  digging  or  deep  ploughing,  the  mould  has 
been  mixed  with  these  unsaturated  earths,  it  ought  to  be 
stirred  at  long  intervals  by  the  plough  or  pick-axe,  before 
being  sowed.  By  presenting  all  the  parts  successively  to 
the  action  of  air  and  water,  they  are  enabled  to  imbibe 
from  them  those  principles  in  which  they  are  deficient ; 
and  thus  the  same  effect  is  produced  upon  them,  as  is 
wrought  upon  marl  or  the  black  ferruginous  earths  by  a 
longer  exposure^  after  they  have  been  taken  from  their 
beds. 


ARTICLE  VII. 

Of  the  Analysis  of  Arable  Soils. 

Though  experience  and  long  observation  may  enable  an 
agriculturist  to  become  acquainted  with  the  nature  and 
degree  of  fertility  of  each  part  of  his  land,  it  will  in  most 
cases  be  convenient  for  him  to  acquire  this  knowledge  by 
shorter  and  more  direct  methods. 


ANALYSIS    OF    ARABLE    SOILS.  45 

I  shall  not  point  out  the  process  of  an  analysis  with  the 
most  minute  exactness ;  this  would  place  it  beyond  the 
skill  of  the  greater  part  of  agriculturists  to  perform ;  and 
the  precision  of  the  results  would  be  useless  for  the  pur- 
pose which  I  have  in  view.  I  shall  limit  myself  to  de- 
scribing the  steps  which  ought  to  be  taken  for  ascertaining 
the  nature  of  the  principal  substances,  whether  earthy, 
saline,  metallic,  vegetable,  or  animal,  which  enter  into  the 
composition  of  a  soil,  whilst  it  is  necessary  to  insist  only 
upon  those  which  concur  most  powerfully  in  rendering  it 
fertile. 

In  analyzing  an  earth,  a  small  quantity  of  it  should  be 
worked  carefully  by  the  hand  before  weighing  it.  The 
first  operation  consists  in  drying  this  specimen  carefully, 
in  order  to  know  the  weight  of  water  it  contains.  For 
this  purpose  it  is  placed  in  a  vessel  over  the  fire,  of  which 
the  heat  must  be  just  sufficient  to  evaporate  the  water. 
This  temperature  must  be  preserved  from  fourteen  to 
twenty  minutes.  In  order  that  no  more  heat  than  is 
necessary  may  be  applied,  it  is  customary  to  put  a  bit  of 
wood  at  the  bottom  of  the  vessel,  or  a  few  bits  of  straw 
into  the  earth  subjected  to  the  experiment,  and  to  with- 
draw it  from  the  fire  as  soon  as  these  begin  to  turn  brown. 

The  next  operation  is  to  weigh  the  earth  a  second  time  ; 
and  the  loss  it  has  sustained  will  be  equal  to  the  weight  of 
the  water  which  has  been  evaporated.  This  operation 
does  not  determine  exactly  the  weight  of  water  contained 
in  the  earth,  because  one  part  of  it  is  nearly  solidified  by 
its  combination  with  some  of  the  earthy  principles,  as 
alumina,  the  salts,  and  many  other  substances,  animal 
and  vegetable  ;  but  it  ascertains  the  quantity  which  served 
to  moisten  the  earth.  In  performing  experiments  upon 
earths  at  a  high  degree  of  temperature,  it  is  easy  to  ascer- 
tain the  power  which  they  have  of  absorbing  moisture, 
and  from  this  some  judgment  may  be  formed  of  their  fer- 
tility. 

As  soon  as  the  quantity  of  free  moisture  contained  in 
the  earth  is  ascertained,  the  sample  must  be  bruised  in  a 
mortar  till  it  becomes  only  a  collection  of  small  particles. 
By  means  of  shaking  upon  a  sieve,  the  gravel  and  other 
hard  substances,  which  enter  into  the  composition,  may  be 
separated  from  the  other  matters,  which,  having  been  ren- 
dered finer,  will  pass  through  readily.  The  coarsest  par- 
ticles should   be   assayed   separately   from   the   others;  if 


46  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

they  are  calcareous,  acids  will  dissolve  them,  producing 
at  the  same  time  an  effervescence ;  to  prove  this,  a  few 
grains  of  them  may  be  put  into  a  glass  containing  good 
vinegar,  or  muriatic  acid  diluted  with  three  or  four  parts 
of  water ;  if  they  are  composed  only  of  carbonate  of  lime, 
they  will  be  entirely  dissolved,  especially  if  the  liquor 
should  still  preserve  its  sharp  and  sour  taste ;  for  in  all 
these  experiments  it  is  necessary  to  use  an  excess  of  acid. 

If  the  coarse  particles  do  not  effervesce  with  an  acid, 
they  are  composed  entirely  of  silica  or  alumina.  These 
are  easily  distinguished  from  each  other,  the  silica  being 
rough  to  the  touch,  scratching  glass,  and  sinking  quickly 
in  water ;  whilst  alumina  is  smooth  and  unctuous  to  the 
touch,  and  mixes  with  water,  in  which  it  remains  some 
time  suspended. 

The  coarse  particles  may  be  composed  by  the  union  of 
the  calcareous,  siliceous,  and  aluminous  earths;  but  in 
this  case  the  acids  have  dissolved  a  part  of  the  calcareous 
particles ;  and,  after  removing  the  acid  which  holds  them 
in  solution,  it  is  easy  to  ascertain  by  the  abovementioned 
characteristics,  whether  the  insoluble  portion  remaining 
in  the  glass  be  silica  or  alumina. 

If  the  coarse  particles  are  only  of  quartzeous  sand  or 
of  pure  silica,  water  and  the  acids  will  produce  no  effect 
upon  them ;  and  their  nature  can  be  easily  determined 
by  the  characteristics  I  have  given  of  silex  and  alumina. 

It  sometimes  happens  that  these  coarse  particles  are 
mixed  with  the  remains  of  animal' or  vegetable  substances 
imperfectly  decomposed ;  but  these  will  be  easily  recog- 
nized by  the  characteristics  which  distinguish  fossil  sub- 
stances. 

Nothing  now  remains  to  be  done  but  to  examine  the 
finely  divided  and  pulverulent  soil,  which  passed  through 
the  sieve ;  this  contains  the  earths,  salts,  and  animal  and 
vegetable  substances,  in  a  state  of  minute  division.  In 
order  to  ascertain  the  nature  and  proportions  of  the  prin- 
ciples contained  in  this  mixture,  it  must  be  first  weigh- 
ed, and  then  boiled  in  four  times  its  weight  of  water, 
from  ten  to  fifteen  minutes  ;  the  whole  should  then  be  well 
stirred,  and  left  to  settle ;  a  precipitate  will  soon  be 
deposited,  consisting  only  of  the  heaviest  portions  of  the 
mass,  usually  of  fine  siliceous  sand ;  the  turbid  liquor 
which  floats  above  being  thrown  on  a  filter,  the  earths 
and  some  salts  not  easily  soluble  remain  upon  the  filter, 


ANALYSIS    OP    ARABLE    SOILS.  47 

and  the  water  charged  with  all  the  soluble  portions  flows 
into  the  vessel  destined  to  receive  it. 

We  find,  by  this  operation,  three  distinct  products ; 
first,  the  precipitate  deposited  at  the  bottom  of  the  vase 
in  which  the  ebullition  was  performed,  consisting  of  the 
finest  sand ;  secondly,  that  remaining  upon  the  filter, 
and  which  consists  of  a  mixture  of  earths  and  insoluble 
salts ;  and,  thirdly,  that  which  contains  in  solution  all  the 
salts  and  animal  and  vegetable  substances  capable  of 
being  dissolved  in  boiling  water.  The  two  first,  after 
they  have  been  dried  with  c^re,  and  their  weight  ascertain- 
ed, must  be  examined  in  order  to  know  the  nature  and 
proportions  of  the  substances  which  compose  them. 

I  have  previously  observed,  that  the  deposit  constitut- 
ing the  first  product,  is  generally  composed  only  of  sil- 
ica ;  if  otherwise,  it  could  be  tested  by  acids,  which  will 
dissolve  all  the  calcareous  portions  of  it,  while  those  parts 
which  are  insoluble  may  be  treated  by  the  means,  which 
I  have  already  pointed  out,  for  separating  alumina  from 
silica. 

For  the  second  part,  which  is  the  one  remaining  on 
the  filter,  it  is  sufficient  to  make  an  analysis  of  it,  by 
pouring  upon  it  muriatic  acid  diluted  with  four  parts  of 
water,  till  it  will  effervesce  no  longer ;  this  will  dissolve 
the  carbonates  of  lime,  and  of  magnesia,  should  there 
be  any  present,  as  well  as  any  oxide  of  iron  ;  the  solu- 
tion being  filtered,  any  substance  not  dissolved  will  re- 
main on  the  filter,  and  must  be  washed  with  water,  till 
the  water  runs  off  tasteless  ;  the  residuum  must  be  dried 
and  weighed ;  it  generally  consists  of  alumina,  and  some 
animal  and  vegetable  matter. 

In  order  to  ascertain  if  the  muriatic  acid  has  dissolved 
any  oxide  of  iron,  stir  it  with  a  bit  of  oak  bark  ;  if  the 
liquor  renders  it  brown  or  black,  it  contains  iron  ;  in  or- 
der to  ascertain  the  quantity,  throw  into  the  liquor  prus- 
siate  of  potash  till  it  will  no  longer  form  a  blue  precipi- 
tate ;  let  it  settle  ;  collect  the  deposit,  and  heat  it  to  red- 
ness ;  that  which  remains  after  this  operation  is  the  oxide 
of  iron,  and  must  be  carefully  weighed. 

When  the  solution  has  been  freed  from  the  oxide  of 
iron,  there  remains  in  it  only  lime,  and  perhaps  a  little 
magnesia;  these  can  be  precipitated  by  means  of  a  so- 
lution of  carbonate  of  soda,  which  must  be  poured  into 
the  muriatic  acid  till   a  precipitate  is  no  longer  thrown 


48  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

down ;  after  having  poured  off  the  liquor,  the  residuum 
must  be  washed  and  dried;  when  its  weight  will  give 
the  quantity  of  carbonate  of  lime  contained  in  the  earthy 
mixture. 

If  the  carbonate  of  lime,  and  the  other  deposits  ob- 
tained, be  of  a  brown  color,  it  is  to  be  presumed,  that 
they  contain  a  mixture  of  animal  or  vegetable  substance,  of 
which  the  quality  and  proportions  may  be  ascertained  by 
throwing  them  upon  a  red-hot  iron,  and  holding  them  over  a 
fire  of  such  a  temperature,  as  will  heat  the  iron  to  white- 
ness ;  if  the  smoke  arising  from  them  have  the  odor  of 
burning  leather,  hair,  or  feathers,  the  substance  contained 
in  them  is  animal ;  but  if  it  have  the  smell  of  wood  smoke, 
it  is  vegetable.  The  two  substances  are  sometimes  com- 
bined, but  the  means  of  ascertaining  in  what  proportions 
are  beyond  the  skill  of  an  agriculturist ;  I  have  therefore 
thought  that  I  ought  to  confine  myself  to  the  experi- 
ment necessary  for  ascertaining  their  presence. 

The  method  I  have  just  described  is  easy,  and  in  the 
power  of  any  agriculturist,  however  little  informed ;  it 
is  not  exact,  but  it  furnishes  results  approximating  near 
enough  to  the  truth,  to  enable  any  one  to  ascertain  the 
nature  and  proportions  of  the  earthy  substances  which 
enter  into  the  composition  of  a  soil.  A  greater  degree 
of  precision  in  the  analysis  would  require  the  employ- 
ment of  many  agents  unknown  to  the  agriculturist,  and 
a  habit  of  analysis  which  he  cannot  be  supposed  to  pos- 
sess. 

But  as  the  salts  play  an  important  part  in  vegetation, 
and  as  all  soils  are  in  some  degree  impregnated  with 
them,  I  believe  I  ought  not  to  dispense  with  pointing  out 
the  means  of  recognising  them,  and  for  this  purpose  I 
shall  be  obliged  to  have  recourse  to  some  particular 
process. 

By  boiling  the  finely  divided  earth  in  water,  we  can 
separate  from  it  all  the  soluble  salts  it  contains,  and  the 
evaporation  of  the  liquid,  which  holds  them  in  solution, 
will  enable  us  to  know  their  natures  and  proportions. 
If  the  operation  be  carefully  conducted,  the  salts  can  be 
obtained  in  crystals,  and,  by  the  character  of  these, 
their  properties  can  be  distinguished.  Nitre  has  a  sharp 
taste,  and  consumes  upon  glowing  charcoal ;  marine  salt 
decrepitates,  and  splits  with  a  sparkling  appearance  over 
the  fire ;  the  sulphate  of  soda  swells  up   with  the   heat, 


NATURE    AND    ACTION    OF    MANURES.  411 

giving  out  an  aqueous  smoke,  and  leaving  a  dry  white 
residuum.  But  when  the  sahs  are  insoluble,  as  phos- 
phate of  lime ;  or  soluble  with  difficulty,  as  sulphate  of 
lime,  water  will  not  act  upon  them,  and  they  remain 
mixed  with  the  earth  without  their  existence  being  sus- 
pected, as  long  as  an  analysis  is  confined  to  the  limits  I 
have  laid  down.  However,  these  substances,  especially 
the  sulphate  of  lime,  influence  so  much  the  quality  of 
soils,  that  it  is  necessary  to  furnish  the  means  for  ascer- 
taining their  existence,  I  will  however  observe,  that 
these  salts  are  contained  in  the  earths  in  so  small  a 
quantity,  as  not  to  influence  sensibly  the  results  of  the 
analysis  I  have  directed,  for  ascertaining  the  natures  and 
proportions  of  the  other  principles  which  essentially  com- 
pose them. 

To  ascertain  if  a  soil  contains  sulphate  of  lime,  (gyp- 
sum, plaster  of  Paris,)  take  an  exact  quantity,  four  hun- 
dred grains  for  example,  mixed  with  one  third  the  quan- 
tity of  powdered  charcoal,  expose  it  in  a  crucible  during 
half  an  hour  to  a  red  heat ;  afterwards  boil  it  for  a  quar- 
ter of  an  hour  in  half  a  pint  of  water,  filter  the  liquor, 
and  expose  it  for  some  days  in  an  open  vessel ;  if  it  form 
a  white  precipitate,  the  soil  contains  sulphate  of  lime, 
and  the  weight  of  the  deposit  will  make  known  nearly 
the  proportion.     (Davy.) 

To  judge  of  the  existence  of  phosphate  of  lime,  digest 
the  earth  in  an  excess  of  muriatic  acid,  evaporate  the 
solution  to  dryness,  wash  the  residuum  in  a  large  quan- 
tity of  water,  and  the  insoluble  phosphate  will  remain 
alone. 


CHAPTER  HI 

OF   THE    NATURE    AND    ACTION    OF    MANURES. 

Under  the  general  head  of  manures  are  comprehended 
all  those  substances  which,  existing  in  the  atmosphere  or 
combining  with  the  soil,  can  be  drawn  in  by  the  organs 
of  plants,  and  contribute  to  the  progress  of  vegetation. 

Manures  are  furnished  by  various  bodies  belonging  to 
the  three  kingdoms  of  nature.  Those  most  commonl/ 
5 


60  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

employed  are  the  results  of  decomposed  vegetable  sub- 
stances, and  some  animal  matters. 

The  salts,  which  likewise  serve  for  manures,  are  im- 
bibed by  the  pores  of  plants,  and  serve  to  stimulate  vege- 
tation. 

By  comprehending  all  these  substances  under  the  gene- 
ric name  of  manures,  too  extensive  a  signification  is  given 
to  the  word.  I  divide  manures  into  two  classes ;  and  in 
order  to  deviate  as  little  as  possible  from  the  customary 
mode  of  expression,  I  shall  call  those  nutritive  manures, 
which  supply  plants  with  nourishment,  and  all  those 
which  excite  the  organs  of  digestion  stimulating  manures. 
These  last  are,  strictly  speaking,  the  seasoning;  the 
spices,  rather  than  the  food. 


ARTICLE   I. 

Of  Nutritive    Manures. 

The  nutritive  manures  are  those  which  contain  juices 
or  other  substances,  which,  being  dissolved  in  water,  or 
otherwise  divided  to  the  most  minute  degree,  are  capable 
of  being  drawn  into  the  organs  of  plants.  All  the  vege- 
table and  animal  juices  are  of  this  description. 

These  substances  are  rarely  employed  in  their  natural 
state  for  the  aliment  of  plants.  It  is  generally  considered 
preferable  to  allow  them  to  putrify  or  ferment ;  the  rea- 
son of  this  is  simple.  Besides  the  decomposition  resulting 
from  this  operation,  which  renders  the  substances  more 
soluble  in  water,  the  gases  produced  by  it,  such  as  the 
carbonic  acid,  the  carburetted  hydrogen,  azote,  and  am- 
monia, furnish  food  for  plants,  or  stimulants  for  their 
organs  of  digestion.  It  is  not,  however,  well  to  prolong 
this  decomposition  too  far ;  for  if  it  be  completed,  there 
will  remain  only  some  fixed  salts,  mixed  with  those  earths 
and  juices  which  have  resisted  its  action.  Besides,  the 
effect  of  manures,  which  have  been  entirely  decomposed, 
is  almost  momentary,  lasting  but  for  a  single  season ; 
whilst  those  which  are  employed  before  arriving  at  this 
state,  continue  to  exert  an  influence  for  several  years.  In 
this  last  case,  the  decomposition,  retarded  by  the  separa- 
tion of  the  manures  into  small   portions,  continues    to  go 


NUTRITIVE    MANURES.  51 

on  gradually  in  the  earth,  and  thus  furnishes  vegetation 
with  its  necessary  aliments  for  a  long  time. 

The  excrements  of  animals,  formed  by  the  digestion  of 
their  food,  have  already  undergone  a  decomposition  which 
has  disorganized  the  principles  of  their  aliments,  and  in  a 
greater  or  less  degree  changed  their  nature.  The  strength 
of  the  digestive  organs,  which  varies  in  each  species  of 
animal,  the  difference  of  food,  and  the  mixture  of  the  di- 
gestive fluids  furnished  by  the  stomach,  modify  these  ma- 
nures to  a  very  considerable  extent. 

The  excrements  of  some  animals,  as  of  pigeons,  fowls, 
&/C,,  are  employed  without  undergoing  any  new  fermenta- 
tion, because  they  consist  mostly  of  salts,  and  contain  but 
few  juices.  Fields  are  often  manured  with  the  excre- 
ments of  sheep,  collected  in  the  sheep-folds,  or  scattered, 
as  in  parks,  by  the  animals  themselves  upon  the  soil ;  but 
in  general  the  dung  of  horses  and  of  horned  cattle  is  made 
to  undergo  a  new  fermentation  before  being  applied  as 
manure. 

The  most  general  method  of  producing  the  fermenta- 
tion of  the  dung  of  quadrupeds,  is,  in  the  first  place,  to 
form  upon  the  ground  of  sheep-folds  and  stables  a  bed  of 
straw  or  dry  leaves.  This  bed  is  covered  with  the  solid 
excrements  of  the  quadrupeds,  and  impregnated  with  their 
urine.  At  the  end  of  fifteen  days  or  a  month,  it  is  carried 
to  a  place  suited  for  fermentation,  and  there  formed  anew, 
care  being  taken  every  day  to  spread  upon  it  litter  and 
the  scatterings  of  the  racks.  The  formation  of  these 
beds,  contributes  much  to  the  healthfulness  of  the  stables 
and  to  the  cleanliness  of  the  animals.  When,  from  a 
scarcity  of  straw,  the  beds  cannot  be  made  of  sufficient 
thickness,  or  renewed  ofi:en  enough,  a  layer  may  be 
formed  of  lime  or  gravel,  broken  fine  and  covered  with 
straw.  These  earths  will  imbibe  the  urine,  and  when 
they  are  penetrated  by  it  may  be  carried  into  the  fields  to 
be  buried  in  the  soil.  The  nature  of  the  earth,  upon 
which  beds  are  formed  in  sheep-folds  or  stables,  should 
vary  according  to  the  character  of  the  soil  which  is  to 
receive  them,  because,  by  attention  to  this,  the  soil  may 
be  improved  as  well  as  manured.  For  argillaceous  and 
compact  earths,  the  layers  should  be  formed  of  gravel 
and  the  remains  of  old  lime  mortars ;  whilst  those  of  fat 
marl  or  of  clayey  mud  should  be  reserved  for  light  and 
dry  soils. 


t>2  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

In  some  countries,  where  good  husbandry  is  much  at- 
tended to,  the  floors  of  the  stables  are  paved  and  slightly 
sloping,  so  that  the  urine  flows  off"  into  a  reservoir,  where 
it  is  fermented  with  animal  and  vegetable  substances,  and 
used  to  water  the  fields  at  the  moment  when  vegetation 
begins  to  be  developed. 

The  art  of  fermenting  dungs  with  litter  is  still  very  in- 
complete in  some  parts  of  France.  In  one  place  they  let 
it  decay  till  the  straw  is  completely  decomposed ;  in 
another  they  carry  it  into  the  fields  as  soon  as  it  is  taken 
from  the  stables.  These  two  methods  are  equally  faulty. 
By  the  first,  nearly  all  the  gases  and  nutritive,  juices  are 
dissipated  and  lost ;  by  the  second,  fermentation,  which 
can  take  place  only  in  masses,  will  be  but  very  imperfectly 
carried  on  in  the  fields,  and  the  rains  can  convey  to  the 
plants  only  that  portion  of  the  nourishment  afforded  by 
the  manure,  which  they  can  obtain  by  a  simple  washing. 

The  most  useful  art  perhaps  in  agriculture,  and  that 
whicli  requires  the  most  care,  is  the  preparation  of  dung- 
heaps.  It  requires  the  application  of  certain  chymical 
principles,  which  it  is  not  necessary  for  me  to  explain, 
since  it  is  sufficient  to  point  out  to  the  agriculturist  the 
rules  by  which*  he  should  be  governed  in  his  proceedings, 
without  requiring  of  him  an  extensive  knowledge  of  the 
theory  upon  which  they  are  founded. 

Solid  substances,  whether  animal,  vegetable,  or  mineral, 
do  not  enter  into  plants  unless  they  are  previously  dis- 
solved in  water,  or  are  drawn  in  with  that  fluid  in  a  state 
of  extreme  division. 

Animal  and  vegetable  substances  which  are  by  their 
nature  insoluble  in  water,  may,  by  being  decomposed,  form 
new  soluble  compounds,  capable  of  furnishing  nourish- 
ment for  plants. 

Animal  and  vegetable  substances  deprived  by  the  ac- 
tion of  water  of  their  soluble  particles,  may,  in  the  course 
of  their  decomposition,  form  new  compounds  susceptible 
of  being  dissolved.  Of  this  I  have  given  instances  in 
speaking  of  mould. 

That  which  renders  the  art  of  employing  dung-heaps 
difficult,  in  proportion  as  it  is  useful,  is,  that  some  meth- 
ods which  are  adopted  occasion  the  loss  of  a  part  of  the 
manure.  In  fact,  when  the  clearings  of  the  farm-yard  are 
carried  fresh  into  the  fields,  and  applied  immediately  to 
the    soil,  vegetation  is  undoubtedly  benefited  by  the  salts 


NUTRITIVE    MANURES.  S3 

and  the  juices  contained  in  them ;  but  the  fibres,  the  fat- 
ness, the  oils,  remain  inactive  in  the  earth ;  and  their 
final  decomposition  is  slow  and  imperfect.  If,  on  the  con- 
trary, the  collections  of  the  farm-yard  be  heaped  up  in  a 
corner  of  it,  the  mass  will  speedily  become  heated,  car- 
bonic acid  gas  will  be  evolved,  and  afterwards  carburetted 
hydrogen,  ammonia,  azote,  &c.  A  brown  liquid,  of  which 
the  color  deepens  gradually  almost  to  black,  moistens  the 
heap,  and  flows  upon  the  ground  around  it ;  all  is  by  de- 
grees disorganized  ;  and  when  the  fermentation  is  com- 
pleted, there  remains  only  a  residue  composed  of  earthy 
and  saline  substances,  mixed  with  a  portion  of  blackened 
fibre,  and  some  carbon  in  powder. 

In  those  places  where  they  do  not  allow  fermentation 
to  arrive  to  this  degree  of  decomposition,  they  still  lose,  by 
mismanagement,  a  considerable  part  of  their  manure. 

The  most  common  method  is,  to  deposit  in  a  corner  of 
the  farm-yard  the  dung  and  litter,  as  it  is  drawn  from  the 
stables,  adding  to  the  mass  every  time  these  are  cleared, 
and  allowing  it  to  ferment  till  the  period  of  sowing  arrives, 
whether  it  be  in  spring  or  autumn,  when  it  is  carried 
upon  the  fields  requiring  it. 

This  method  presents  many  imperfections.  In  the  first 
place,  several  successive  layers  being  formed,  no  two  of 
them  can  have  undergone  the  same  degree  of  fermenta- 
tion ;  in  some  it  will  have  gone  on  for  six  months,  and  in 
others  but  for  fifi;een  days.  In  the  second  place,  the  heap, 
being  exposed  to  rains,  will,  by  frequent  washings,  have 
parted  with  nearly  all  its  salts  and  soluble  juices.  In  the 
third  place,  the  extractive  portions  of  the  lower  and  cen- 
tral parts  of  the  mass,  the  mucilage,  the  albumen,  and 
the  gelatine,  will  be  entirely  decomposed ;  and,  lastly, 
those  gases  which  nourish  plants,  if  developed  at  their 
roots,  will  have  escaped  into  the  air;  and  Davy  has  ob- 
served, that,  by  directing  these  emanations  beneath  the 
roots  of  the  turf  in  a  garden,  the  vegetation  was  rendered 
very  superior  to  that  in  the  vicinity. 

How  long  should  dunghills  be  allowed  to  ferment ;  and 
what  methods  ought  to  be  pursued  in  forming  them? 
This  question  leads  us  to  cast  a  glance  upon  the  nature  of 
dunghills ;  and  it  is  not  till  after  having  ascertained  the 
difference  amongst  them,  that  it  can  be  answered. 

The  principal  parts  of  vegetables  which  are  employed 


64  CHYMISTKY    APPLIED    TO    AGRICULTURE. 

as  manure  contain  mucilage,  gelatine,  oils,  sugar,  starch, 
extractive  matter,  and  often  albumen,  acids,  salts,  &c, 
with  an  abundance  of  fibrous  matter,  insoluble  in  water. 

The  different  substances  afforded  by  animals,  including 
all  their  excretions,  are  gelatine,  fibrine,  mucus,  fat,  albu- 
men, urea,  uric  and  phosphoric  acids,  and  some  salts. 

The  greatest  part  of  the  substances,  constituting  ani- 
mals and  vegetables,  are  soluble  in  water  ;  and  it  is  evi- 
dent that  in  that  state  they  can  be  employed  as  manures 
without  fwevious  fermentation ;  but  it  is  necessary,  that 
those  which  contain  much  insoluble  matter  should  be 
decomposed  by  fermentation,  because  by  that  process  their 
nature  is  changed,  and  they  form  new  compounds,  which, 
being  capable  of  solution,  can  pass  into  the  organs  of 
plants. 

Messrs.  Gay-Lussac  and  Thenard  have  obtained,  by  an 
analysis  of  the  woody  fibre,  oxygen,  hydrogen,  and  es- 
pecially more  carbon,  than  from  any  other  part  of  the 
plant,  and  they  have  determined  their  several  proportions. 
We  know  that  fermentation  carries  off"  much  carbon  ;  it 
is  then  evident  that,  by  causing  the  fermentation  of  the 
vegetable  fibre,  the  principle  which  forms  its  distinguish- 
ing characteristic  will  be  gradually  diminished,  and  that 
it  will  no  longer  be  a  body  insoluble  in  water.  It  is  in 
this  manner  that  woody  plants  and  the  driest  leaves  are 
converted  into  manure. 

But  as  all  the  solid  parts  of  plants  contain  fibres  which 
cannot  be  rendered  soluble  in  water,  but  by  a  long  period 
of  fermentation  ;  and  as  it  is  in  the  fibre  that  carbon,  a 
principle  so  necessary  to  vegetation,  chiefly  exists,  the 
fermentation  of  plants  is  indispensable  to  the  procuring  of 
the  best  part  of  their  manure. 

The  custom  of  appropriating  some  crops  whilst  green 
to  the  manuring  of  the  ground,  may  perhaps  be  objected 
to ;  but  I  have  observed,  that  in  that  case  the  plants  are 
buried  in  the  earth  at  the  time  of  flowering  ;  and  whilst 
they  are  succulent,  and  their  fibres  soft,  and  but  little 
formed ;  and  that  warmth  and  the  action  of  water  in  the 
earth  was  sufficient  to  decompose  them :  this  would  not 
take  place  if  the  stalks  were  dried  and  hardened  by  the 
formation  of  the  grain. 

The  dung  of  quadrupeds  may  be  mixed  advantageously 
with  the  earth  at  the  time  of  being  taken  from  the 
■table,  if  it  contain  no  litter  ;  but  if  it  does,  it  appears  to 


NUTRITIVE     MANURES.  56 

me  better  to  cause  it  to  undergo  a  slight  fermentation,  in 
order  to  dispose  the  straw  or  leaves  of  which  it  is  com- 
posed to  become  manure. 

It  is  necessary,  in  producing  the  fermentation  of  dung 
and  litter,  to  use  certain  precautions  by  which  the  incon- 
veniences arising  from  the  usual  mode  may  be  avoided. 

Instead  of  heaping  up  in  large  masses  the  collections  of 
the  barn-yard  and  stables,  and  allowing  them  to  rot  un- 
covered, and  exposed  to  the  changes  of  weather,  they 
should  be  placed  under  a  shed,  or  be  at  least  protected 
from  the  rain  by  a  roof  of  straw  or  heath.  Separate  lay- 
ers should  be  formed  of  each  clearing  of  the  stables, 
cow-house,  and  sheep-pens.  These  layers  should  be  from 
a  foot  and  a  half  to  two  feet  in  thickness ;  and  when  the 
heat,  produced  in  them  by  fermentation,  rises  in  the 
centre  to  more  than  95°,  or  when  the  mass  begins  to 
smoke,  it  should  be  turned,  to  prevent  decomposition  from 
going  too  far. 

Fermentation  should  be  arrested  as  soon  as  the  straw 
contained  in  the  heap  begins  to  turn  brown,  and  its  tex- 
ture to  be  decomposed.  To  do  this,  the  mass  may  be 
spread,  or  carried  into  the  fields,  to  be  immediately  mixed 
with  the  soil ;  or  there  may  be  mixed  with  it  mould,  plas- 
ter, turf,  sweepings,  &>c. 

When  the  dung  is  not  of  the  usual  consistency,  as  is 
the  case  with  that  of  neat  cattle  during  the  spring  and 
autumn,  it  ought  to  be  employed  immediately,  as  I  have 
already  stated  ;  but  if  it  be  impossible  to  apply  it  to  the 
fields  whilst  recent,  it  should  be  mixed  with  earths  or 
other  dry  and  porous  substances,  which  may  serve  as  ma- 
nures for  the  fields  destined  to  receive  it. 

Upon  nearly  all  our  farms  the  dung  of  quadrupeds  is 
exposed  to  the  open  air,  without  the  protection  of  a  shed, 
as  soon  as  it  is  removed  from  the  stables;  and  is  thus 
washed  by  the  rains,  which  carry  off  all  the  salts,  urine, 
and  soluble  juices,  and  form  at  the  foot  of  the  mass  a 
rivulet  of  blackish  fluid,  which  is  either  wholly  evaporated 
or  lost  in  the  ground.  In  proportion  as  fermentation  ad- 
vances, new  soluble  combinations  are  formed,  so  that  all 
the  nutritive  and  stimulating  principles  of  the  dung  gradu- 
ally disappear,  till  there  remain  only  some  weak  portions 
of  the  manure,  intermingled  with  stalks  of  straw  which 
have  lost  all  their  goodness. 

To  remedy   as  much  as  possible  an  abuse  so  injurious 


56  .      CHYMISTRY    APPLIED    TO    AGRICULTURE.   ' 

to  agriculture,  it  is  necessary  at  least  to  dig  a  deep  ditch 
to  receive  all  the  juices  which  flow  from  the  dunghill,  in 
order  that  they  may  be  used  in  the  spring  upon  the  corn 
or  grass  lands ;  or  they  may  be  preserved  to  water  the 
grass  lands  with,  after  the  first  mowing.  A  large  cask, 
fixed  upon  a  small  cart,  and  which  can  be  filled  by  means 
of  a  hand  pump,  is  sufficient  for  this  purpose.  Beneath 
the  tap  of  the  cask  must  be  fitted  a  narrow  chest  about 
four  feet  long,  with  the  bottom  pierced  with  holes,  through 
which  the  liquor  may  be  scattered.  This  mode  of  water- 
ing, when  used  after  mowing,  produces  wonderful,  effects 
upon  the  crop  of  the  following  year. 

Before  deciding  upon  the  question,  whether  dung  and 
litter  should  or  should  not  be  made  to  ferment,  it  is  neces- 
sary to  take  into  consideration  the  nature  of  the  soil  to  be 
manured.  If  this  be  compact,  clayey,  and  cold,  it  is 
better  that  fermentation  should  not  have  taken  place,  as 
two  effects  will  be  produced  by  the  application  of  the 
manure  in  an  undecomposed  state.  In  the  first  plape  it 
will  improve  the  soil  by  softening  and  dividing  it,  so  as  to 
render  it  permeable  by  air  and  water ;  and  in  the  next 
place  it  will,  whilst  undergoing  the  successive  processes 
of  fermentation  and  decomposition,  warm  the  soil.  If,  on 
the  contrary,  the  soil  be  light,  porous,  calcareous,  and 
warm,  the  thoroughly  fermented  manure,  or  short  muck^ 
as  it  is  called  by  farmers,  is  preferable,  because  it  gives 
out  less  heat,  and  instead  of  opening  the  earth,  already 
too  porous,  to  the  filtrations  of  water,  it  moderates  the 
flow  of  that  fluid.  Long  experience  has  made  these  truths 
known  to  observing,  practical  farmers. 

When  it  is  required  to  apply  dung  to  any  particular 
kind  of  soil,  it  is  necessary  that  it  should  be  used  accord- 
ing to  a  knowledge  of  its  qualities.  The  dung  of  animals 
bearing  wool  is  the  warmest;  next,  that  of  horses;  whilst 
that  of  cows  and  oxen  contains  the  least  heat  of  any. 

Soft  or  fluid  animal  substances  change  the  most  easily  ; 
and  the  progress  of  their  decomposition  is  rapid  in  pro- 
portion to  the  diminution  of  the  quantity  of  earthy  salts 
contained  in  them.  Their  decomposition  produces  an 
abundance  of  ammonial  gas.  This  circumstance  distin- 
guishes them  from  vegetable  substances,  the  decomposition 
of  which  gives  rise  to  the  production  of  that  gas,  only  as 
far  as  they  contain  a  small  portion  of  albumen.  It  is  par- 
ticularly  to  the   developement  of  ammonial   gas,    which, 


NUTRITIVE    MANURES.  57 

combined  with  gelatine,  passes  into  plants,  that  we  can 
attribute  the  wonderful  effect  produced  upon  vegetation 
by  certain  dry  animal  substances,  of  which  we  shall  speak 
presently. 

Next  to  the  dung  of  animals,  of  which  I  have  just 
spoken,  the  urine  of  horned  cattle  and  of  horses  is  the 
most  abundant  manure  which  can  be  used  in  agriculture  ; 
and  it  is  not  without  regret  that  I  see  every  day  so  little 
pains  taken  to  collect  it.  I  have  already  observed,  that 
in  those  countries  where  agriculture  is  conducted  with  the 
most  care  and  skill,  all  the  stables  are  floored,  and  the 
bottoms  of  them  gently  sloping,  so  as  to  conduct  all  the 
urine  into  a  reservoir,  where  the  remains  of  rape-seed, 
flax,  wild  cabbage,  human  excrements,  &c.  &.c.  are  thrown 
into  it  to  undergo  fermentation.  In  the  spring,  when 
vegetation  begins  to  be  developed,  this  fermented  liquor 
is  carried  into  the  fields  to  water  the  crops. 

There  are  few  animal  substances  of  which  the  nature 
varies  as  much  as  that  of  urine;  the  quality  of  food,  or 
the  state  of  health,  produces  a  sensible  change  in  it. 
The  urine  of  animals  is  more  or  less  abundant  and  active 
in  its  qualities,  in  proportion  as  their  food  is  juicy  or  dry. 
Those  which  live  upon  dry  fodder  give  less  urine  than 
those  which  are  fed  upon  green  herbage ;  but  that  of  the 
first  contains  a  greater  quantity  of  salts  than  that  of  the 
last;  and  that  which  is  produced  directly  by  drink,  con- 
tains less  animal  matter  than  that  which  is  secreted  from 
the  blood  by  the  urinary  organs.  There  are  different 
states  of  individuals,  which  may  explain  satisfactorily  the 
disagreements  in  the  results  which  have  been  given,  by 
the  numerous  analyses  which  have  been  made  of  this 
fluid. 

Mr.  Brandt  has  found  the  urine  of  a  cow  to  contain, 

Water 65 

Phosphate  of  lime 5 

Muriate  of  potash  and  of  ammonia  .     .     15 

Sulphate  of  potash 6 

Carbonate  of  potash  and  of  ammonia     .       4 
Urea 5 


100 
Messrs.   Fourcroy  and  Vauquelin   have   extracted  from 
that  of  the  horse, 


58  CHYMISTRY    APPLIED    TO    AGRICULTURE. 


Carbonate  of  lime 
Carbonate  of  potash 
Benzoate  of  soda  . 
Muriate  of  potash 

Urea 

Water  and  mucilage 


11 

9 

24 

9 

7 

940 


1,000 

An  analysis  of  human  urine  by  M.  Berzelius  afforded, 

Water 933 

Urea 30.1 

Uric  acid 1 

Muriate   of    ammonia,    free    lactic    acid, 

lactate  of  ammonia,  and  animal  matter  17.4 


981.5 

The  remainder  is  composed  of  sulphates,  phosphates, 
and  muriates. 

It  may  be  seen  from  these  analyses,  that  there  is  a  wide 
difference  in  the  urine  of  various  animals,  but  that  all  con- 
tain salts  which  enter  into  plants,  with  the  water  by  which 
they  are  held  in  solution ;  and  draw  in  at  the  same 
time  those  animal  portions,  which,  like  urea,  are  easily 
soluble,  and  can  be  decomposed  without  difficulty. 

Amongst  the  principles  contained  in  urine,  there  are 
some  salts  undecomposable  by  the  digestive  organs  of 
vegetables ;  such  are  the  phosphate  of  lime,  the  muriate 
and  the  sulphate  of  potash.  These  can  serve  only  to  ex- 
cite and  stimulate  the  organs ;  but  the  urea,  the  mucilage, 
the  uric"  acid,  and  other  animal  matters,  must  be  con- 
sidered as  eminently  nutritive.  Urine  in  its  recent  state 
should  never  be  employed  as  manure ;  it  acts  with  too 
much  force,  and  has  a  tendency  to  dry  the  plants ;  it 
should  therefore  be  either  mixed  with  water,  or  allowed  to 
ferment. 

Urine  is  very  useful  for  moistening  all  those  substances 
which  enter  into  composts ;  it  increases  the  fertilizing 
properties  of  each  one  of  them,  and  facilitates  the  fermen- 
tation of  those  which  need  to  be  decomposed  before  yield- 
ing their  nutritive  qualities. 

Urine,  when  combined  with  plaster,  lime,  &c.,  forms  a 
very  active  manure  for  cold  lands. 

Bones  have,  at  the  present  time,  become,  in  the  hands 
of  the  agriculturist,  a  powerful  agent  in  fertilizing  the  soil. 


NUTRITIVE    MANURES.  59 

These  parts  of  animals  are  principally  composed  of  phos- 
phate of  lime  and  of  gelatine.  Those  bones  which  are 
most  usually  employed,  contain  about  equal  quantities  of 
phosphate  and  gelatine.  The  bones  of  the  ox  yield  from 
fifty  to  fifty-ftve  per  cent,  of  gelatine ;  those  of  the  horse 
from  thirty-six  to  forty ;  and  those  of  the  hog  from  forty- 
eight  to  fifty. 

The  bones  of  young  animals  contain  more  gelatine  than 
those  of  older  animals,  and  have  a  less  compact  texture. 
The  bones  of  the  feet  of  the  elk,  the  roe-buck,  stag,  and 
hare  afford,  upon  analysis,  from  eighty  to  ninety  per  cent, 
of  phosphate. 

When  bones  are  to  be  employed  as  a  manure,  they 
should  be  ground  fine,  and  thrown  into  a  heap  to  ferment. 
As  soon  as  this  action  shall  have  commenced,  so  as  to 
give  out  a  penetrating  odor,  the  mass  should  be  spread 
upon  the  earth,  and  be  afterwards  mixed  with  it;  or  it 
may  be  thrown  upon  the  seed,  and  buried  in  the  ground 
with  it.  When  seeds  are  sown  in  furrows,  it  is  a  good 
method  to  place  some  of  the  ground  bones  in  the  furrows 
with  them. 

In  some  countries  the  fat  and  a  great  part  of  the  gela- 
tine are  extracted  from  bones,  by  boiling  them  in  water, 
before  selling  them  for  agricultural  purposes.  But  by  this 
operation  they  are  deprived  of  a  great  part  of  their  fertil- 
izing powers.  Upon  carefully  observing  the  appearance 
of  a  mass  of  bones  under  fermentation,  I  found  the  sur- 
face of  a  part  of  them  to  be  covered  with  a  thin  coating 
of  an  unctuous  substance,  sharp  and  biting  to  the  taste. 
This  appeared  to  me  to  be  formed  by  the  combination  of 
gelatine  with  ammonia ;  this  last  being  always  developed 
during  the  decomposition  of  all  animal  substances.  The 
observations  of  M.  D'Arcet,  to  whom  we  are  indebted  for 
a  very  valuable  work  upon  gelatine,  support  this  opinion. 

It  is  possible,  that,  when  the  ground  bones  are  em- 
ployed without  having  been  first  submitted  to  the  com- 
mencement of  a  fermentation,  the  gelatine  is  gradually 
decomposed  in  the  ground,  and  the  same  result  at  length 
produced  ;  or,  we  can  conceive  that  water,  acting  upon 
the  bones,  will  dissolve  the  gelatine,  and  transmit  it  to 
plants  ;  and  in  both  these  cases  the  influence  of  the  bones 
upon  vegetation  is  very  great,  whether  it  be  considered 
as  a  purely  nutritive  manure,  or  in  the  double  connexion 
of  a  nutritive  and  stimulating  substance. 


60  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

When  bones  are  calcined  in  a  close  vessel,  they  yield 
oil  and  carbonate  of  ammonia ;  the  proportion  of  the 
phosphate  is  not  sensibly  diminished ;  but  the  gelatine  is 
decomposed.  There  remains  after  the  operation  from  six- 
ty-six to  seventy-two  per  cent,  of  the  weight  of  the  bones 
employed.  This  residue,  broken  and  pulverized  with  care, 
is  of  great  use  in  the  process  of  refining  sugar.  After 
having  been  used  in  this  process,  and  become  impreg- 
nated with  ox-blood  and  animal  carbon,  I  have  found  it 
to  be  one  of  the  best  manures  which  I  could  employ  for 
trefoil  and  clover.  It  should  be  scattered  with  the  hand 
upon  the  plants,  when  vegetation  begins  to  be  developed 
in  the  spring. 

Some  of  the  dry  parts  of  animals,  as  the  horns,  hoofs, 
and  claws,  approach  closely  to  bones  in  the  nature  of  their 
constituent  principles ;  but  the  proportions  of  these  va- 
ry prodigiously.  In  such  parts,  gelatine  constitutes  the 
largest  portion ;  and  for  this  reason  they  are  more  es- 
teemed as  manure  than  the  bones.  M.  Merat-Guillot  has 
found  but  twenty-seven  per  cent,  of  phosphate  of  lime  in 
the  horn  of  a  stag,  and  M.  Hatchett,  by  an  analysis  of 
five  hundred  grains  of  the  horn  of  an  ox,  gained  only  one 
fifth  part  of  earthy  residuum,  of  which  a  little  less  than 
one  half  was  phosphate  of  lime. 

The  clippings  and  parings  of  horns  form  an  excellent 
manure,  of  which  the  effect  is  prolonged  during  a  suc- 
cession of  years,  owing  to  the  difficulty  with  which  water 
penetrates  them,  and  the  little  tendency  they  have  to  fer- 
ment. 

A  very  good  manure  is  likewise  formed  from  wool.  Ac- 
cording to  the  ingenious  experiments  of  M.  Hatchett,  hair, 
feathers,  and  wool  are  only  particular  combinations  of  gela- 
tine with  a  substance  analogous  to  albumen;  water  can 
only  dissolve  them  by  means  of  fermentation,  which  takes 
place  slowly,  and  after  a  long  time. 

One  of  the  most  surprising  instances  of  fertile  vegeta- 
tion that  I  have  ever  seen,  is  that  of  a  field  in  the  neigh- 
bourhood of  Montpellier,  belonging  to  a  manufacturer  of 
woollen  blankets.  The  owner  of  this  land  causes  it  to  be 
dressed  every  year  with  the  sweepings  of  his  work-shops ; 
and  the  harvests  of  corn  and  fodder  which  it  produces, 
are  astonishing. 

It  is  well  known,  that  the  hairs  of  wool  transpire  a  fluid 
which  hardens  upon   their  surface,   but  which  possesses 


NUTRITIVE    MANURES.  61 

the  property  of  being  easily  soluble  in  water.  This  sub- 
stance has  received  the  name  of  animal  sweat ;  the  water 
in  which  wool  has  been  washed  contains  so  much  of  it,  as 
to  make  it  very  valuable  as  a  manure. 

I  saw,  thirty  years  since,  a  wool  merchant  in  Montpel- 
lier,  who  had  placed  his  wash-house  for  wool  in  the  midst 
of  a  field,  a  great  part  of  which  he  had  transformed  into 
a  garden.  In  watering  his  vegetables  he  had  used  no 
other  water  than  that  of  the  washings;  and  the  beauty 
of  his  productions  was  so  great,  as  to  render  his  garden 
a  place  of  general  resort.  The  Genoese  collect  with  care, 
in  the  south  of  France,  all  they  can  find  of  shreds  and 
rags  of  woollen  fabrics,  to  place  at  the  foot  of  their  olive 
trees. 

According  to  the  analysis  of  M.  Vauquelin,  this  animal 
sweat  is  a  soapy  substance,  consisting  of  a  base  of  potash, 
with  an  excess  of  oily  matter,  and  containing,  besides, 
some  acetate  of  potash,  a  little  of  the  carbonate  and  of 
the  muriate  of  the  same  base,  and  a  scented  animal 
matter. 

The  dung  of  birds  is  another  very  valuable  manure ; 
differing  from  that  of  quadrupeds  in  the  food's  being  better 
digested;  in  containing  more  animal  mjitter,  being  richer 
in  salts,  and  aflfording  some  of  the  principles  which  are 
found  in  the  urine  of  four-footed  animals. 

The  dung  of  those  sea-fowls,  which  are  so  numerous  in 
the  islands  of  the  Pacific  ocean,  and  of  which  the  excre- 
ment furnishes  an  important  article  of  commerce  with 
South  America,  as,  according  to  the  accounts  of  M.  Hum- 
boldt, they  import  into  Peru  fifty  shiploads  of  it  annually, 
contains,  besides  a  great  quantity  of  uric  acid  partly  satu- 
rated by  ammonia  and  potash,  some  phosphate  of  lime,  of 
ammonia,  and  of  potash,  as  well  as  some  oily  matter. 
Davy  found  the  dung  of  a  cormorant  to  contain  some  uric 
acid. 

The  good  effects  resulting  from  the  use  of  pigeons' 
dung,  in  our  country,  has  caused  it  to  be  carefully  collected. 
One  hundred  parts  of  this,  when  fresh,  yielded  to  Davy 
twenty-five  parts  of  matter  soluble  in  water,  whilst  the  same, 
after  having  undergone  putrefaction,  gave  but  eight ; 
whence  this  able  chymist  concluded,  with  reason,  that  it 
was  necessary  to  employ  it  before  being  fermented.  This 
is  a  warm  manure,  and  may  be  scattered  by  the  hand 
6 


63  CHYMISTRY   APPLIED    TO   AGRICULTURE, 

before  covering  the  seed  ;  or  it  may  be  used  in  the  spring^ 
upon  strong  lands,  when  vegetation  appears  languid. 

The  excrement  of  the  domestic  fowl  approaches  nearly 
in  its  qualities  to  that  of  the  pigeon,  without,  however,  pos- 
sessing the  same  degree  of  power.  It  contains  also  some 
uric  acid,  and  may  be  applied  to  the  same  purposes  as 
pigeons'  dung. 

In  the  south  of  France,  where  they  raise  many  silk- 
worms, they  make  great  use  of  the  larvas,  after  the  silk 
has  been  spun  from  the  cocoons.  They  are  spread  at  the 
foot  of  the  mulberry  and  other  trees,  of  which  the  vegeta- 
tion is  in  a  languishing  condition ;  and  this  small  quantity 
of  manure  reanimates  them  surprisingly.  Upon  distilling 
some  of  these  larvas,  I  found  more  ammonia  than  I  have 
ever  met  with  in  any  other  animal  matter. 

Night  soil  forms  an  excellent  manure;  but  farmers 
allow  it  to  be  wasted,  because  it  is  too  active  to  be  em- 
ployed in  its  natural  state,  and  they  know  not  how  either 
to  moderate  its  action,  or  to  appropriate  it  during  different 
stages  of  fermentation  to  the  wants  of  various  kinds  of 
plants. 

In  Belgium,  which  has  been  the  cradle  of  enlightened 
agriculture,  and  where  good  modes  of  cultivation  are  con- 
tinued and  constantly  improved,  they  make  astonishing 
use  of  this  kind  of  manure.  The  first  year  of  its  decom- 
position, they  cultivate  upon  the  soil  to  which  it  is  ap- 
plied, oleaginous  plants,  such  as  hemp  and  flax  ;  and  the 
second  year  sow  the  land  with  corn.  They  likewise  mix 
water  with  urine,  and  use  it  to  water  the  fields  in  the 
spring,  when  vegetation  begins  to  unfold.  This  substance 
is  likewise  dried  and  scattered  upon  fields  of  cabbage. 

The  Flemings  value  this  kind  of  manure  so  much,  that 
the  cities  set  a  high  rate  upon  the  privilege  of  disposing 
of  the  cleansings  of  their  privies ;  and  there  are,  in  each 
one  of  them,  sworn  officers  for  the  assistance  of  those  who 
wish  to  make  purchases.  These  officers  know  the  degree 
of  fermentation  suited  to  each  kind  of  plant,  and  to  the  dif- 
ferent periods  of  vegetation. 

We  shall  find  great  difliculty  in  bringing  this  branch  of 
industry  to  the  same  degree  af  perfection  amongst  us,  that 
it  has  arrived  at  in  Belgium,  because  our  farmers  do  not 
realize  its  importance,  and  have  a  repugnance  to  employ- 
ing this  kind  of  manure.  But,  could  they  not  collect  care- 
fully  all  these  matters,  mix   them   with  lime,  plaster,  or 


NUTRITIVE   MANURES,  63 

gravel,  till   the  odor    was    dispelled,  and    then    carry    the 
whole  upon  the  fields  ? 

Already,  in  most  of  our  great  cities,  the  contents  of  the 
privies  are  used  for  forming  poudrette:  this  pulverulent 
product  is  sought  for  by  our  agriculturists,  who  acknowl- 
edge its  good  effects;  let  us  hope,  that,  becoming  more 
enlightened,  they  will  employ  the  fecal  matter  itself,  as 
being  more  rich  in  nutritive  principles,  and  abounding 
equally  in  salts ;  they  can  easily  govern  and  moderate  the 
too  powerful  action  of  this,  by  fermentation,  or  what  is  still 
better,  by  mixing  with  it  plaster,  earth,  and  other  absorb- 
ents, to  correct  the  odor. 

As  ^dunghills  are  the  riches  of  the  fields,  a  good  agri- 
culturist will  neglect  no  means  of  forming  them ;  it  ought 
to  be  his  first  and  daily  care,  for  without  dung  there  is  no 
harvest.  The  scarcity  of  dunghills,  or  what  is  the  same 
thing,  the  bad  state  of  the  crops,  sufficiently  proves  the  pre- 
judices, by  which  the  peasant  is  everywhere  governed,  and 
the  habitual  blindness  with  which  he  proceeds  in  his  labors. 
In  our  country,  many  of  those  who  cultivate  the  land, 
know  only  the  kinds  of  straw  which  are  suitable  for  fur- 
nishing manure,  and  in  a  dunghill  of  litter,  consider  them 
as  acting  the  principal  part,  whereas  they  are  only  feeble 
accessories. 

According  to  the  experiments  of  Davy,  the  straw  of  bar- 
ley contains  only  two  per  cent,  of  substance  soluble  in  water, 
and  having  a  slight  resemblance  to  mucilage  ;  the  remainder 
consists  entirely  of  fibre,  which  can  be  decomposed  only 
afi;er  a  long  time,  and  under  circumstances  calculated  to 
facilitate  the  operation. 

I  do  not  believe  that  there  is  in  the  whole  vegetable 
kingdom,  an  aliment  affording  so  little  nutriment,  eitjier  for 
plants  or  animals,  as  the  dry  straw  of  grain  ;  serving  only 
to  fill  the  stomachs  of  the  latter,  and  furnishing  to  the 
former  but  about  one  hundredth  part  of  its  weight  of  solu- 
ble manure. 

Weeds,  leaves  of  trees,  and  all  the  succulent  plants 
which  grow  so  abundantly  in  ditches  and  waste  lands, 
under  hedges,  and  by  the  road  side,  if  cut  or  pulled  when 
in  flower,  and  slightly  fermented,  furnish  from  twenty  to 
twenty-five  times  more  manure  than  straw  does.  These 
plants,  carefully  collected,  furnish  to  the  agriculturist  an 
immense  resource  for  enriching  his  lands.  Besides  the 
advantage    arising    from   the   manure  furnished   by   these 


64  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

plants,  the  agriculturist  will  find  his  account  in  prevent- 
ing the  dissemination  of  their  seeds,  which,  by  propagat- 
ing in  the  fields,  deprive  the  crops  of  the  nourishment  of 
the  soil.  The  turf,  that  borders  fields  and  highways,  may 
be  made  to  answer  the  same  purpose,  by  cutting  it  up  with 
all  the  roots  and  the  earth  adhering  to  them,  rotting  the 
whole  in  a  heap,  and  afterwards  carrying  the  mass  upon 
the  fields,  or  what  is  still  better,  by  burning  it,  and  dress- 
ing the  land  with  the  products  of  the  combustion. 

If  straw  did  not  serve  as  beds  for  animals,  and  did  not 
contribute,  at  the  same  time,  to  their  health  and  cleanliness, 
it  would  be  better  to  cut  the  ears  of  corn  and  leave  the 
stalks  in  the  fields ;  since  they  serve  only  as  absorbents  of 
the  true  manures. 

It  is  always  said  that  barn-yard  manure,  besides  its  nu- 
tritive virtues,  possesses  the  advantage  of  softening  hard 
lands,  and  rendering  them  permeable  by  air  and  water.  I 
do  not  deny  the  truth  of  this  ;  I  even  acknowledge  that  it 
owes  this  property  almost  entirely  to  the  straw  which  it  con- 
tains ;  but  the  same  effect  would  be  produced  by  burying 
the  straw  upon  the  spot. 

Besides  the  characteristic  of  providing  plants  with  food, 
the  various  kinds  of  dung  possess  other  qualities,  which 
add  to  their  fertilizing  powers.  Dung,  as  it  is  applied  to 
the  ground,  is  never  so  much  decomposed  as  to  have  ceased 
fermenting;  and  from  the  moment  it  is  mixed  with  the 
soil  it  produces  in  it  a  degree  of  warmth  favorable  to  vege- 
tation, and  serving  to  guard  the  young  plants  against  the 
effects  of  those  sudden  returns  of  cold  in  the  atmospheric 
temperature,  which  are  so  often  experienced.  On  account 
of  the  viscous  fluids  which  it  contains,  dung  is  not  easily 
dried,  unless  it  be  in  contact  with  the  air.  It  therefore 
preserves  the  roots  of  the  plants  in  a  state  of  moisture; 
and  supports  vegetation  at  those  periods,  when,  without  it, 
plants  would  perish  from  drought.  It  likewise  contains 
many  salts  which  are  transmitted  by  water  to  plants,  serv- 
ing to  animate  and  excite  their  functions.  The  various 
kinds  of  dung,  mixed  with  earth,  may  be  considered  in 
the  light  of  amendments  to  the  soil ;  and  in  this  view  they 
ought  to  vary  according  to  the  nature  of  the  earth  to  be 
improved.  Compact  soils  require  to  be  separated  and 
warmed ;  they  require,  then,  those  manures  which  have 
been  but  slightly  fermented,  and  that  are  the  richest  in 
salts.     Calcareous  and   light  earths   require  oily  manures, 


NUTRITIVE    MANURES,  "65 

which  decompose  slowly,  and  can  retain  water  for  a  long 
time,  to  furnish  it  to  the  wants  of  plants  in  seasons  of 
drought. 

It  is  by  separating  these  principles,  that  we  may  be  able 
to  appropriate  the  various  kinds  of  manure  to  each  species 
of  soil  and  plant :  the  attention  of  agriculturists  is  already 
directed,  upon  this  point,  to  the  composition  of  mixtures 
of  manures,  called  composts.  These  are  formed  by  ar- 
ranging, one  above  another,  beds  of  different  kinds  of 
manure,  taking  care  to  correct  the  faults  of  one  by  the 
properties  of  another,  in  such  a  manner  as  to  produce  a 
mixture  suited  to  the  soil  to  be  enriched  by  it. 

For  example,  if  it  be  required  to  form  a  compost  for  a 
clayey  and  compact  soil ;  the  first  bed  must  be  made  of 
plaster,  gravel,  or  mortar  rubbish ;  the  second,  of  the  lit- 
ter and  excrements  of  horses,  or  sheep ;  the  third,  of  the 
sweepings  of  yards,  paths,  and  barns,  of  lean  marl,  dry 
and  calcareous;  of  mud  deposited  by  rivers,  of  the  fecal 
matter  collected  upon  the  farm,  the  remains  of  hay,  straw, 
etc.,  and  this  in  its  turn  must  be  covered  with  a  laying  of 
the  same  materials  as  the  first.  Fermentation  will  take 
place  first  in  the  beds  of  dung,  and  the  liquor  flowing  from 
these  will  mingle  with  the  materials  of  the  other  layers; 
when  the  mass  exhibits  the  signs  which  I  have  pointed 
out,  as  indicating  decomposition  to  be  sufficiently  ad- 
vanced, it  must  be  carried  into  the  fields,  care  being  first 
taken  to  mix  well  the  substances  composing  the  different 
layers. 

If  the  compost  be  designed  to  manure  a  light,  porous, 
and  calcareous  soil,  it  must  be  formed  of  materials  of  a 
very  different  character.  In  this  case  it  is  necessary  that 
argillaceous  principles  should  prevail  ;  the  substances  must 
be  compact,  the  dung  of  the  least  heating  kind,  and  the 
fermentation  continued,  till  the  materials  form  a  yielding 
and  glutinous  paste ;  the  earths  must  be  clayey,  half  baked, 
and  pounded,  or  consisting  of  fat  and  argillaceous  marl, 
and  mud  from  the  sea  coast.  Of  these  all  the  layers  must 
be  formed. 

By  following  these  principles  in  my  operations,  I  have 
completely  changed  the  nature  of  an  ungrateful  soil  in  the 
neighbourhood  of  one  of  my  manufactories.  Over  this  soil, 
composed  of  calcareous  earth  and  light  sand,  I  spread, 
during  several  years,  some  calcined  clayey  earth;  and  this 
land,  upon  which  I  could  formerly  raise  only  stone  fruit, 
6* 


66 


CHYMISTRY    APPLIED    TO    AGRICULTURE. 


has  become  adapted  to  fruit  containing  kernels ;  and  pro- 
duces excellent  wheat,  whereas  before  it  bore  only  scanty 
crops  of  oats  and  rye. 


ARTICLE   IT. 

Of  Stimulating  Manures. 

I  HAVE  hitherto  spoken  only  of  those  manures  which 
contain,  at  the  same  time  with  aliments  necessary  for 
vegetation,  the  salts  which  are  inseparable  from  them ; 
and  which  pass,  in  a  state  of  solution,  into  the  organs  of 
plants  to  stimulate  their  action.  I  shall  now  speak  particu- 
larly of  these  salts,  explaining  in  what  manner  they  act, 
and  how  their  utility  in  vegetable  economy  differs  materially 
from  that  of  the  alimentary  principles  ;  and  showing  that 
they  can  often  be  so  employed  as  to  increase  the  activity  of 
vegetation. 

It  appears  from  the  results  of  the  critical  experiments 
which  M.  Saussure  has  made  upon  these  substances,  that 
the  salts  and  extracts,  when  dissolved  in  water,  are  absorbed 
by  the  roots  of  plants. 

The  absorption  of  hurtful  salts  is  easy  and  abundant,  in 
proportion  as  the  plant  is  languishing,  sickly,  or  mutilated. 
From  this  principle,  established  by  experiments,  it  follows 
that  the  absorption  of  fluids  and  salts  by  the  plants  is  not 
a  passive  and  purely  physical  faculty ;  but  one,  which  is 
determined  by  those  laws  of  vitality,  which  govern  the 
plant  during  life.  It  is  only  when  the  power  of  these  laws 
is  weakened  by  a  sick  or  languishing  state  of  the  plant, 
that  external  agents  can  act  upon  it  in  an  absolute  manner. 
Plants  do  not  draw  in  indifferently,  or  in  the  same  quan- 
tities, all  substances  which  can  be  held  in  solution  by  wa- 
ter ;  they  absorb,  from  preference,  those  which  are  least 
viscid. 

From  the  preceding  statements  it  is  rational  to  conclude, 
that  plants  do  not  maintain  a  strictly  passive  state  in  regard 
to  their  aliments  ;  but  that  to  a  certain  degree  they  have  a 
preference,  and  taste,  respecting  them;  and  that  the  physi- 
cal laws  predominate,  to  the  injury  of  the  vital  organization, 
in  proportion  to  the  sickly  or  languishing  condition  of  the 
plant. 


STIMULATING   MANURES.  67 

All  the  soft  and  fibrous  portions  of  plants,  are  evidently 
the  product  of  the  elaboration  carried  in  their  organs,  of 
the  juices  and  gases  by  which  they  are  nourished.  The 
saline  particles,  which  plants  contain,  are  unchanged,  and 
such  as  are  furnished  by  the  soil. 

Whatever  may  be  the  variety  of  products  presented  to 
us  by  the  vegetable  kingdom,  the  elements  which  compose 
them  are  few  in  number.  They  contain  only  oxygen,  car- 
bon, hydrogen,  and  azote,  combined  in  an  immense  variety 
of  proportions  ;  some  hundredths  more  or  less,  in  the  propor- 
tions of  these  constituent  principles,  often  cause  an  aston- 
ishing difference  in  the  character  of  their  products.  It  is 
this  which  occasions  the  slightest  alteration  produced  in  the 
organs  to  give  rise  to  new  compounds,  bearing  no  resem- 
blance to  the  first. 

No  one  has  ever  disputed  that  the  juices,  the  oils,  the 
resins,  the  fibre,  and  other  essential  parts  of  vegetation, 
are  the  result  of  the  action  of  the  different  organs  of 
plants ;  and  that  the  elements  composing  them  were  those 
of  the  bodies  by  which  they  are  nourished,  and  which 
each  combines  in  a  manner  peculiar  to  itself,  and  fitted  to 
its  own  Organization.  There  is,  in  all  this,  nothing  like 
creation,  but  simply  decomposition  upon  one  side,  and,  upon 
the  other,  a  new  combination  of  the  elements,  in  different 
proportions. 

Many  philosophers,  in  other  instances  very  correct,  have 
asserted  that  plants  themselves  form,  even  by  the  act  of  vege- 
tation, salts  and  earths ;  but,  as  science  has  advanced,  it 
has  been  ascertained  that  none  of  the  experiments  cited  by 
them  have  been  made  with  exactness.  Some  have  watered 
plants  with  distilled  water ;  others  have  raised  them  in 
washed  sand  ;  nearly  all  have  allowed  free  access  of  the 
air  to  them ;  many  have  analyzed,  with  a  certain  degree 
of  care,  the  soil  upon  which  they  raised  their  plants ;  and 
nearly  all  have  concluded,  that  the  salts  and  earths  which 
they  found  in  them,  and  of  which  they  could  demonstrate 
neither  the  existence,  nor  even  the  quantity  if  found,  in 
the  different  substances  concurring  to  produce  vegetation, 
must  be  the  work  of  the  plant.  But  does  not  the  often 
disturbed  atmosphere  frequently  change  the  salts,  and  the 
earths,  which  it  deposits  upon  plants  ?  Does  not  the  dust 
which  it  carries,  alight  upon  the  upper  surfaces  of  leaves 
and  branches  ?     Water,  the  best  distilled,  according  to  the 


68  CHYMISTRY    APPLIED  TO    AGRICULTURE. 

experiments  of   Davy,  contains  some  alkaline  and  earthy 
atoms. 

Messrs.  Schrader  and  Braconnot  have  published  the  re- 
sults of  their  experiments,  by  vi^hich  they  have  been  led  to 
believe,  that  salts  and  earths  are  created  in  the  organs  of 
plants;  but  M.  Lassaigne  has  proved,  that  the  salts  and 
earths,  contained  in  the  developed  plant,  are  the  same  as 
those  that  are  found  in  the  seed  from  which  they  sprang. 

M,  Th.  de  Saussure,  whose  opinion  upon  these  matters 
is  of  great  weight,  has  proved  that  plants  do  not  create  any 
of  these  substances. 

Besides,  if  the  formation  of  certain  salts  be  a  power  of 
the  plant  itself,  why  does  not  the  salsola  afford  more  ma- 
rine salt  when  it  grows  at  a  distance  from  the  sea  ?  Why, 
under  the  same  circumstances,  does  not  the  "  tamarisk" 
furnish  more  sulphate  of  soda?  and,  finally,  why  does  the 
turnsol  remain  destitute  of  salt-petre,  if  raised  upon  a  soil 
which  does  not  contain  it? 

Be  this  doctrine  as  it  may,  there  are  two  practical  truths 
which  we  do  know ;  the  first  is,  that  certain  salts  enter, 
if  I  may  so  speak,  as  natural  elements  into  the  composition 
of  some  plants;  since  it  is  found  that  they  languish 
in  earths  not  containing  those  substances;  and  that  the 
plants  absorb  them  abundantly,  when  they  are  present. 
The  second  is,  that  the  salts  ought  always  to  be  united  with 
manures ;  the  excellence  of  which  is  increased,  in  propor- 
tion to  the  quantity  they  contain,  provided  it  do  not  exceed 
the  wants  of  the  plants,  and  that  the  action  be  not  too 
energetic. 

I  may  add,  that  a  plant  absorbs,  from  preference,  the 
salt  most  analogous  to  its  nature.  The  salsola,  which 
grows  by  the  side  of  the  tamarisk,  sucks  up  from  the  earth 
marine  salt;  whilst  the  tamarisk  imbibes  from  it  the  sul- 
phate of  soda.  It  is  proved  by  the  analysis  of  plants  of 
difierent  kinds,  that  have  been  raised  upon  the  same 
ground,  that  they  do  not  furnish  the  same  salts,  or  that,  at 
least,  they  present  a  great  difference  in  the  quantities  they 
contain. 

The  salts  are  necessary  to  plants  ;  they  facilitate  the  ac- 
tion of  their  organs  so  much,  that  they  are  often  employed 
without  mixture. 

Limestone  submitted  to  the  action  of  fire  loses  the  car- 
bonic acid,  which  is  one  of  its  constituent  principles,  and 


STIMULATING    MANURES.  o9 

the  result  is  a  whitish  stone,  opaque  and  sonorous,  of  a 
sharp  and  burning  taste,  absorbing  water  with  noise  and 
heat,  and  forming  with  it  a  paste,  which  is  a  perfect  hydrate. 
Good  limestone  may  be  deprived  of  50  per  cent,  of  its 
weight  by  calcination,  but  it  is  seldom  that  the  heat  of  the 
kilns  is  sufficient  to  deprive  it  of  more  than  from  35  to  40 
per  cent,  when  the  carbonate  is  dry. 

As  soon  as  lime  is  exposed  to  the  air,  it  absorbs  moisture 
from  it  with  great  readiness  ;  gradually  cracking  and  break- 
ing in  pieced.  It  likewise  absorbs  the  carbonic  acid  con- 
tained in  the  atmosphere,  and  is  thus  insensibly  reduced  to 
an  impalpable  powder. 

In  this  manner,  lime  resumes  the  principles  of  which  it 
had  been  deprived  by  calcination,  and  is  reconstituted  lime- 
stone, or  calcareous  carbonate,  without  regaining  its  solidity. 
In  proportion  as  the  recomposition  goes  on,  the  lime  loses 
the  properties  which  it  had  acquired  from  the  action  of 
fire ;  it  ceases  to  be  caustic,  its  solubility  in  water  is  di- 
minished, and  its  affinity  for  that  fluid  becomes  almost 
nothing. 

The  lime  used  in  agriculture  is  that  which  has  been 
slacked  by  air.  Unslacked  lime  destroys  vegetation,  at 
least  if  it  be  not  combined  with  manures  which  moderate 
its  action,  or  with  such  bodies  as  can  furnish  enough  car- 
bonic acid  to  saturate  it. 

We  are  indebted  to  Davy  for  some  experiments  which 
throw  a  great  light  upon  the  action  of  lime  upon  vegetation. 
He  has  proved  that  the  fibrous  portion  of  plants,  deprived 
of  all  the  particles  which  can  be  dissolved  by  water,  presents 
another  series,  soluble  after  having  been  for  some  time 
macerated  with  lime.  Thus  lime  may  be  very  efficaciously 
employed,  when  it  is  wished  to  convert  dry  wood  or  fibrous 
roots,  and  stalks,  to  the  nourishment  of  plants.  Limestone 
broken,  and  lime  completely  restored  to  the  state  of  a 
carbonate,  do  not  produce  this  effect ;  it  is  necessary 
to  employ  lime  slacked  with  water,  and  mixed  with  a  fresh 
portion  of  that  fluid,  and  the  fibrous  substances  must  remain 
for  some  time  exposed  to  th6  action  of  this  solution.  In 
the  case  of  which  I  have  just  spoken,  the  lime  renders  sol- 
uble and  suited  to  the  nourishment  of  plants,  some  sub- 
stances, which,  in  their  natural  state,  do  not  possess  this 
characteristic ;  and  for  this  purpose  the  use  of  it  may  be 
very  advantage6us.  Thus,  when  it  is  desirable  to  convert 
ligneous  and  fibrous  plants  into  manure,  it  may  be  done  by 
treating  them  with  lime. 


70  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

If  it  be  required  to  employ,  as  manure,  some  substances, 
whether  animal  or  vegetable,  which  are  by  nature  soluble 
in  water,  their  mixture  with  lime  forms  new  compounds  of 
natures  completely  different  from  their  constituent  principles, 
but  which  may,  in  time,  become  very  proper  for  the  nutri- 
ment of  plants  :  this  requires  some  explanation. 

The  compounds  formed  by  lime  with  nearly  all  the  soft 
animal  or  vegetable  substances  which  will  combine  with 
it,  are  insoluble  in  water;  accordingly,  lime  destroys  or 
greatly  diminishes  the  property  of  fermentation  in  the 
larger  part  of  them ;  but  these  same  compounds  at  length 
undergo  a  change  from  being  exposed  for  a  length  of  time  to 
the  constant  action  of  air  and  water ;  the  lime  passing  to  the 
state  of  a  carbonate,  and  the  animal  and  vegetable  substances 
being  gradually  decomposed,  and  furnishing  new  products 
capable  of  supplying  nourishment  to  plants;  so  that  lime 
answers  two  great  purposes  for  nutriment ;  first,  it  disposes 
certain  insoluble  bodies  to  form  by  their  decomposition  solu- 
ble compounds;  and,  secondly,  it  prolongs  the -action  and 
nutritive  virtue  of  some  soft  and  insoluble  animal  and  vege- 
table substances,  beyond  the  term  they  would  continue  to 
act  if  they  were  not  made  to  enter  into  combination  with 
lime. 

Very  striking  instances  of  the  facts  which  I  have  just 
stated,  may  be  found  in  some  of  the  operations  performed 
in  various  branches  of  manufactures.  For  instance,  in 
the  process  of  refining  sugars  to  free  them  from  the  vege- 
table extract  and  the  albumen  which  they  contain,  the  milk 
of  lime  is  employed,  which,  combining  with  these  sub- 
stances, rises  to  the  surface  of  the  liquid  in  the  form  of  a 
thick  and  insoluble  foam  or  scum  ;  this,  if  carried  immedi- 
ately into  the  fields,  destroys  vegetation,  but  if  deposited  in  a 
ditch  during  a  year,  it  forms  one  of  the  most  fertilizing 
manures  with  which  I  am  acquainted.  I  have  established 
this  fact  by  having  employed,  in  this  manner,  during  the 
period  of  a  dozen  years,  the  abundant  foam  arising  from  the 
first  operations  performed  upon  the  sugar  of  beets  in  my 
manufactory. 

From  the  explanation  which  I  have  given  of  the  manner 
in  which  lime  acts,  we  may  draw  some  conclusions  in  regard 
to  its  uses,  and  to  the  manner  in  which  it  should  be  em- 
ployed in  order  to  have  the  results,  arising  from  its  applica- 
tion, conform  to  those  which  have  been  produced  by  en- 
lightened experiments. 


STIMULATING    MANURES.  71 

It  is  acknowledged  that  lime  is  principally  useful  upon 
fallow  lands  which  are  broken  up ;  upon  grass  lands, 
whether  natural  or  artificial,  which  are  prepared  for  culti- 
vation ;  and  upon  muddy  lands,  which  are  to  be  put  into 
a  state  fit  for  culture.  It  is  well  known,  that  in  all  these 
cases  there  exists  in  the  land  a  greater  or  less  quantity  of 
roots,  which,  by  the  application  of  lime,  may  be  made  to 
serve  more  immediately  for  manure,  by  the  solubility  it 
will  give  to  the  new  products  formed  by  them ;  but  this 
effect  can  be  produced  neither  by  spreading  the  lime  on 
the  land  at  the  time  of  sowing  the  seed,  nor  by  throwing 
it  upon  the  soil  without  covering  it,  nor  by  sprinkling  it 
upon  the  plants  which  have  begun  to  unfold  ;  it  is  neces- 
sary to  scatter  it  upon  the  land  before  the  first  tilling,  and 
only  as  fast  as  it  can  be  mixed  with  the  soil,  as  lime  loses 
its  strength  by  exposure  to  the  air.  Subsequent  tillages 
mix  it  more  intimately  with  the  soil,  and  place  it  in  con- 
tact with  the  roots  and  stalks  upon  which  it  is  to  act,  and 
at  the  end  of  some  months  this  action  is  completed. 

Independently  of  this  effect,  which,  in  my  opinion,  is 
the  most  important,  lime  exercises  other  powers,  which 
make  it  a  very  valuable  agent  in  agriculture.  It  cannot 
be  denied,  that  the  long  existence  and  the  barrenness  of 
a  marshy  or  turfy  soil,  give  rise  in  such  lands  to  myriads 
of  insects,  which  repeated  tillages,  and  frequent  changes 
of  crops,  can  destroy  only  in  a  great  length  of  time;  whilst 
the  mixture  of  lime  with  the  earth  performs  the  work  im- 
mediately. It  is  certain,  that  some  plants  which  injure 
the  soil  and  the  crops,  escape  every  tilling ;  but  are  imme- 
diately destroyed  by  the  action  of  lime.  It  is  clear,  that 
to  produce  these  effects,  the  lime  must  be  applied  in  the 
caustic  state  ;  the  mode  of  preparing  it  is  as  follows. 

As  lime  absorbs  water  with  avidity,  exhaling  vapor  and 
producing  noise  and  heat,  and  crumbling  into  pieces,  that 
liquid  may  be  thrown  upon  it,  till  the  whole  mass  is  re- 
duced to  a  dry  and  impalpable  powder ;  and  it  is  in  this 
state  that  it  must  be  used. 

In  order  to  preserve  the  husbandman  from  the  delete- 
rious effects  upon  the  lungs,  of  this  light  powder,  it  is  best 
to  mix  it  with  some  moistened  earth  ;  and  in  order  that  it 
may  preserve  all  its  virtue,  it  is  necessary  that  it  should  be 
immediately  buried  in  the  soil  by  ploughing. 

The  custom  of  employing  air-slacked  lime,  which  is 
lime  in  the  state  of  a  sub-carbonate,  is  spreading  in  France 


72  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

every  year,  and  is  productive  of  good  results.  This  lime 
is,  undoubtedly,  less  active  than  that  which  has  been 
slacked  by  water ;  but  it  requires  fewer  precautions  in  the 
use  of  it,  and  is  not  liable  to  so  many  inconveniences. 

When  lime  has  been  acted  upon  by  the  air,  till  it  is 
reduced  to  the  state  of  an  impalpable  powder,  it  is  used 
with  great  advantage  by  mixing  it  with  dunghill  manure ; 
it  serves  to  correct  the  acidity  arising  from  the  decompo- 
sition of  certain  portions  of  this,  such  as  the  mash  of 
grapes,  6lc.  &c.,  and  it  absorbs  the  juices  that  would  flow 
off  and  be  lost,  or  would  be  too  rapidly  decomposed  ;  it 
likewise  fixes  the  gases,  which  would  otherwise  ascend 
into  the  atmosphere.  This  mixture  spread  upon  the  fields 
excites  vegetation,  warms  cold  soils,  divides  those  which 
are  compact,  regulates  the  fermentation  of  manures,  and 
furnishes  to  plants,  gradually,  and  in  proportion  to  their 
wants,  the  nutritive  principles  with  which  it  is  impreg- 
nated. 

Lime  slacked  by  air  does  not  entirely  lose  the  property 
of  being  soluble  in  water,  and  when  used  it  is  carried  into 
the  organs  of  plants  by  that  liquid,  producing  those  good 
effects  which  arise  from  the  employment  of  saline  sub- 
stances, in  small  quantities. 

Limestone  saturated  with  carbonic  acid,  though  it  may 
be  reduced  to  powder,  does  not  produce  any  of  the  good 
effects  arising  from  the  use  of  quick-lime,  or  of  that  which 
has  been  slacked  by  air.  Its  almost  sole  use  is  to  divide 
compact  earths,  to  facilitate  the  passage  of  water  through 
them  ;  and  to  dispose  them  to  yield  more  readily  to  tillage. 

Limestone  often  contains  some  magnesia,  which  exer- 
cises a  singular  power  in  modifying  the  action  of  the  lime. 
M.  Tennant  obtained  from  20  to  22  per  cent,  of  magnesia 
from  limestone,  in  which  the  lime  was  in  the  proportion  of 
only  from  29  to  31  per  cent.,  by  throwing  upon  this  mix- 
ture a  little  more  nitric  acid,  diluted  with  water,  than  was 
necessary  to  saturate  it;  the  liquor  remained  turbid,  and 
of  a  whitish  color. 

I  have  always  observed  that  all  earths,  of  whatever 
nature,  containing  magnesia,  render  the  waters  covering 
them  whitish;  and  that  the  agitatiou-jof  these  waters  by 
the  wind  takes  from  them  all  their  transparency.  When 
such  waters  form  ponds  or  pools,  they  are  called  white 
waters. 


STIMULATING    MANURES,  73 

Magnesian  earths  possess  but  little  fertility ;  and  when 
the  lime  employed  for  agricultural  purposes  contains  mag- 
nesia, its  beneficial  effects  do  not  follow.  In  order  to  ac- 
count for  this  difference  of  action,  it  is  necessary  to  take 
into  consideration,  that  magnesia  has  less  affinity  for  car- 
bonic acid  than  lime  has,  and  that,  consequently,  when 
the  two  earths  are  mingled  together,  the  magnesia  pre- 
serves its  causticity,  even  when  the  lime  is  saturated  with 
carbonic  acid,  and  brought  back  to  the  state  of  lime-stone. 
Thus  it  appears  that  magnesia  can  preserve  its  caustic 
properties,  and  exercise  its  deleterious  effects  upon  vege- 
tation, during  a  long  time. 

The  use  of  plaster,  or  gypsum,  which  has  become  com- 
mon in  Europe  as  a  manure,  is  one  of  the  most  important 
improvements  that  has  ever  been  made  in  agriculture.  It 
has  even  been  introduced  into  America,  where  it  was 
made  known  by  Franklin  upon  his  return  from  Paris. 
As  this  celebrated  philosopher  wished  that  the  effects  of 
this  manure  should  strike  the  gaze  of  all  cultivators,  he 
wrote  in  great  letters,  formed  by  the  use  of  the  ground  plas- 
ter, in  a  field  of  clover  lying  upon  the  great  road  to  Wash- 
ington, "  This  has  been  plastered."  The  prodigious  vege- 
tation which  was  developed  in  the  plastered  portion  led 
him  to  adopt  this  method.  Volumes  upon  the  excel- 
lences of  plaster  would  not  have  produced  so  speedy  a  revo- 
lution. From  that  period  the  Americans  have  imported 
great  quantities  of  plaster  of  Paris. 

There  are,  however,  some  tracts  of  country  where  the 
use  of  plaster  has  been  attempted  without  success.  But 
this  arose  from  its  being  one  of  the  original  constituents 
of  the  soil,  which  derived  no  advantage  from  the  addition 
of  a  new  quantity.  The  existence  of  this  salt,  naturally, 
in  those  lands  upon  which  plaster  produced  little  or  no 
effect,  has  been  proved  by  analysis. 

Gypsum  is  a  compound  of  sulphuric  acid  and  lime,  con- 
taining more  or  less  of  the  water  of  crystallization.  A 
moderate  heat  deprives  it  of  its  water  of  crystallization, 
and  renders  it  opaque.  It  can  then  be  reduced  to  powder, 
and  employed  in  that  state.  Though  the  prepared  gyp- 
sum absorbs  water  with  avidity,  and  its  consistency  is 
affected  by  the  mixture,  it  may  be  preserved  many  months 
without  its  properties  being  sensibly  affected.  Nothing 
more  is  necessary  for  this  purpose  than  to  head  it  up  in 
tight  casks. 

7 


74  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Gypsum  carefully  broken  is  likewise  much  used ;  and 
there  are  some  farmers  who  attribute  to  it  the  same  effica- 
cy as  is  possessed  by  that  prepared  by  heat.  I  have  my- 
self made  some  comparative  experiments,  and  observed, 
that  the  baked  planter  evidently  produced  a  little  more 
effect  the  first  year,  but  during  the  three  years  which  fol- 
lowed, the  difference  was  almost  nothing. 

The  gypsum  is  scattered  by  the  hand  at  the  time  when 
the  leaves  of  the  plants  begin  to  cover  the  ground,  and  it 
is  best  to  take  advantage  of  a  light  rain  for  the  operation,  as 
it  is  thought  to  be  beneficial  to  have  the  leaves  moistened, 
in  order  that  they  may  retain  a  small  portion  of  the 
powder. 

The  effect  of  the  gypsum  is  perceptible  during  three  or 
four  years.  The  use  of  it  can  be  resumed  at  the  end  of 
that  time.  The  quantity  in  which  it  is  usually  employed 
is  from  2f  cwt.  to  3^  cwt.  per  acre. 

Much  has  been  said  upon  the  effects  of  plaster.  Some 
have  pretended  that  its  action  ought  to  be  attributed  to 
the  force  with  which  it  absorbs  water.  But  it  solidifies 
that  liquid,  and  does  not  part  with  it  either  to  the  atmo- 
sphere, or  to  any  other  surrounding  body  ;  so  that  this 
doctrine  does  not  appear  well  founded.  Besides,  if  its 
action  were  from  this  cause,  it  would  be  momentary, 
and  would  cease  after  the  first  rains ;  and  this  is  con- 
tradicted by  experience.  Moreover,  it  is  believed  that 
the  broken  gypsum  has  not  the  property  of  absorbing 
water ;  and  yet  it  produces  nearly  the  same  effects  as  thl 
baked  and  powdered  plaster. 

Others  have  thought  that  plaster  acted  only  by  favoring 
the  putrefaction  of  animal  substances  and  the  decompo- 
sition of  manures.  But  Davy  has  refuted  this  opinion  by 
direct  experiment,  placing  it  beyond  a  doubt,  that  the 
mixture  of  plaster  with  manures,  whether  animal  or  vege- 
table, does  not  facilitate  decomposition. 

There  are  others,  again,  who  attribute  the  effects  of 
plaster  to  its  stimulating  properties ;  and  these  adopt,  in 
its  utmost  extent,  the  opinion  which  I  have  formed  upon 
the  subject.  It  still  remains,  however,  to  be  explained, 
why  this  salt,  which  is  not  more  stimulating  than  many 
others,  acts  with  so  much  better  effect,  and  why  its  action 
is  continued  during  several  years,  whilst  that  of  others  is 
exhausted  in  so  much  less  time ;  why  this  salt  never  dries 
plants,  whilst  the  others,  if  employed  in  excess,  burn  them 
up  and  destroy  them.     These  are  problems  which  remain 


STIMULATING    MANURES.  75 

to  be  solved,  and  of  which  the  solution  cannot  be  found 
in  the  stimulating  properties  of  the  plaster. 

Hitherto  it  has  been  sufficient  to  state  the  good  effects 
of  plaster,  in  order  that  agriculture  might  be  enriched  by 
so  important  a  discovery.  The  fact  alone  is  sufficient  for 
the  farmer,  and  it  is  not  the  only  one  in  which  the  theory 
can  add  nothing  to  the  practice.  I  shall,  however,  give 
here  a  few  of  my  ideas  upon  the  action  of  plaster ;  and 
I  publish  them  with  the  more  confidence,  because  they 
appear  to  me  to  be  deduced  from  well-established  anal- 
ogies. 

It  is  proved,  that  those  salts  which  have  a  base  of  lime 
or  alkali  are  the  most  abundant  in  plants.  Analysis  also 
shows  that  the  different  salts  do  not  exist  in  the  same  pro- 
portions, either  in  plants  of  different  kinds,  or  in  the  dif- 
ferent parts  of  the  same  plant. 

On  the  other  hand,  observation  shows  us  every  day, 
that  these  substances,  to  be  beneficial  to  plants,  must  be 
presented  to  them  in  proper  proportions ;  for  if  too  great 
a  quantity  of  salts  easily  soluble  in  water  be  mixed  with 
the  soil,  the  plants  will  wither  and  die ;  though  they  will 
languish,  if  totally  deprived  of  the  salts.  A  little  marine 
salt,  mixed  with  dung  and  spread  upon  the  soil,  excitee 
the  organs  of  plants  and  promotes  vegetation  ;  but  too 
much  will  produce  a  pernicious  effect  upon  them. 

If  we  now  consider  that  salts  can  act  upon  plants,  only 
in  proportion  to  their  solubility  in  water,  through  which 
medium  they  are  conveyed,  we  can  conceive,  that  those 
which  are  least  soluble  will  be  productive  of  the  greatest 
advantage. 

Water  can  hold  in  solution  at  any  one  time  but  a  small 
portion  of  these  saline  substances ;  and  as  they  will  al- 
ways be  conveyed  into  plants  in  the  same  proportions, 
their  effect  will  be  equal  and  constant,  and  will  be  con- 
tinued till  the  soil  be  exhausted  of  the  salts.  Tiie  length 
of  this  period  will  be  according  to  the  quantity  of  them 
which  is  contained  in  the  soil,  and  to  the  plants  not  being 
rendered  liable  to  receiving  more  of  them  than  it  needs. 

The  solubility  of  plaster  in  water  appears  to  be  pre- 
cisely of  the  degree  most  beneficial ;  300  parts  of  water 
will  dissolve  only  1  of  plaster.  Its  action  is  therefore 
constant  and  uniform,  without  being  hurtful.  The  organs 
of  plants  are  excited  by  it  without  .being  irritated  and  cor- 
roded, as  they  are  by  those  salts  which,  being  more  soluble 


76  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

in  water,  are  carried  more  abundantly  into  plants,  pro- 
ducing upon  them  the  most  injurious  effects. 

The  greater  part  of  those  salts  which  are  found  in 
plants  serve  no  purpose  of  nourishment ;  they  are  gene- 
rally useful  only  as  stimulating  the  organs  and  aiding  di- 
gestion. Animals,  as  they  enjoy  the  power  of  locomotion, 
can  easily  procure  for  themselves  these  stimulants  and 
whatever  is  needful  for  the  exercise  of  their  offices,  and 
they  take  only  such  quantities  and  in  such  proportions  as 
are  suitable  for  them.  But  plants -have  no  other  medium 
than  air  and  water,  through  which  to  receive  their  sup- 
plies ;  and  this  last  transmits  to  them  indiscriminately  all 
which  it  can  dissolve  from  the  soil  ;  whence  it  follows, 
that  the  best  saline  manures  are  those  that  can  be  only 
gradually  dissolved. 

This  principle  is  applicable  to  all  manures  of  whatever 
nature.  There  is,  however,  this  difference  in  the  effects  of 
manures  purely  nutritive,  and  of  the  stimulating  or  saline 
manures;  if  the  first  be  too  abundant,  the  plant  absorbs 
more  nourishment  than  it  can  readily  digest,  and  becomes 
affected  by  a  kind  of  obesity  ;  the  texture  of  its  organs  is 
rendered  soft,  loose,  and  spongy,  and  unable  to  give  to 
their  products  the  due  degree  of  consistency ;  whilst,  on 
the  contrary,  if  the  stimulating  manures  be  supplied  too 
profusely,  and  especially  if  they  be  of  kinds  very  soluble 
in  water,  the  organs  of  the  plants  are  dried  and  parched 
by  the  excess  which  they  receive. 

Those  animal  substances  that  are  the  most  slowly  de- 
composed, and  which  by  their  decomposition  always  give 
rise  to  soluble  products,  are  the  best  of  all  manures  :  of 
this  bones,  horns,  and  wool,  afford  a  sufficient  proof. 
These  substances  possess  the  advantage  of  affording  to 
plants  their  suitable  aliments,  almost  always  combined 
with  a  stimulant,  such  as  ammonia,  of  which  the  too  irri- 
tating action  is  moderated  by  its  union  with  carbonic 
acid  or  with  animal  matter. 

The  ashes  of  turf  and  of  pit  coal  produce  wonderful 
effects  upon  grass  lands.  The  first  of  these  often  con- 
tains gypsum,  but  frequently  only  silica,  alumina,  and 
oxide  of  iron.  From  ashes  of  pit  coal  I  have  obtained 
by  analysis  sulphuret  of  lime. 

The  ashes,  produced  by  the  combustion  of  wood  in  our 
common  domestic  fires^  give  rise  to  some  very  remarkable 
results.     Without  being  leached  these  ashes  are  much  too 


GERMINATION.  77 

active;  but  after  having  been  deprived,  by  the  action  of 
water,  of  nearly  all  their  salts,  and  employed  in  this 
state,  under  the  name  of  buck-ashes,  they  still  produce 
great  effect. 

The  action  of  the  buck-ashes  is  most  powerful  upon 
moist  lands  and  meadows,  in  which  they  not  only  facili- 
tate the  growth  of  useful  plants,  but  if  employed  con- 
stantly for  several  years,  they  will  free  the  soil  from  weeds. 
By  the  use  of  them,  land  constantly  drenched  with  water 
may  be  freed  from  rushes,  and  prepared  for  yielding 
clover  and  other  plants  of  good  kinds.  Wood  ashes  pos- 
sess the  double  property  of  amending  a  wet  and  clayey 
soil  by  dividing  and  drying  it,  and  of  promoting  vegeta- 
tioo  by  the  salts  they  contain. 


CHAPTER  IV. 

OF    GERMINATION. 


Oxygen,  heat,  and  water  are  almost  the  sole  agents 
in  the  act  of  germination. 

Pure  water,  when  imbibed  by  a  seed,  as  a  grain  of 
wheat,  for  instance,  increases  its  volume,  and  mcilitates 
the  developement  of  the  germ.  But  the  first  of  these 
effects  is  entirely  physical,  and  takes  place  in  the  dead 
as  well  as  in  the  living  seed,  as  has  been  proved  by  M.  de 
Saussure.  Water  changes  neither  the  odor  nor  the  taste 
of  seeds.  A  grain  of  wheat,  deprived  of  its  vital  prin- 
ciple, is,  by  the  action  of  water,  disposed  to  putrefaction ; 
whilst  in  one  which  is  living,  the  fluid  contributes  to  the 
developement  of  a  succession  of  new  powers. 

There  are  some  seeds  that  can  germinate  under  water; 
but  it  is  only  through  the  quantity  of  air  contained  in  that 
liquid  that  it  then  operates  in  assisting  germination.  The 
developement  of  the  germ  will  not  take  place  in  water 
completely  deprived  of  air;  and  when  the  water  contains 
but  little  air,  it  is  necessary,  to  its  producing  the  same 
effect,  that  the  volume  of  it  should  be  increased. 

Seeds,  whilst  germinating,  absorb  oxygen,  and  surround 
themselves  with  an  atmosphere  of  carbonic  acid.  This, 
however,  does  not  take  place  if  the  seed  be  In  Contact 
7* 


78  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

with  the  atmospheric  air,  or  with  water  containing  mucii 
air. 

If  seeds  are  secluded  from  air  and  moisture  whilst  fresh 
and  succulent,  they  putrefy ;  but  if  previously  dried,  they 
do  not  undergo  this  change,  but  preserve  their  power  of 
germination,  till  exposure  to  air  and  moisture  calls  it  into 
action. 

The  activity  of  germination  is  proportioned  to  the  de- 
gree of  oxygen  contained  in  the  air.  The  larger  seeds 
imbibe  more  of  this  gas  than  the  smaller. 

Seeds,  whilst  germinating,  exhale  only  carbonic  acid  ; 
and  the  volume  of  oxygen  they  consume  is  always  equal 
to  the  volume  of  carbonic  acid  produced.  All  these 
results  have  been  ascertained  by  the  beautiful  experi- 
ments of  M.  de  Saussure.  It  appears,  then,  that  the  only 
agent  in  germination  is  oxygen ;  the  only  product  car- 
bonic acid.  The  seed  parts  with  a  certain  portion  of 
carbon,  and  the  oxygen  combines  with  no  other  principle 
of  the  seed.  For  if  a  seed  be  made  to  germinate  in  100 
inches  of  atmospheric  air,  containing  21  inches  of  oxygen, 
it  will  be  found  that  germination  has  produced  14  cubic 
inches  of  carbonic  acid,  and  that  there  remains  7  cubic 
inches  of  free  oxygen  in  the  portion  of  atmosphere  in 
which  the  process  of  germination  has  been  going  on. 
It  is  evident,  then,  that,  in  this  first  stage  of  vegetation, 
water  does  not  furnish  the  seed  with  any  additional  prin- 
ciple, and  that  it  is  not  itself  decomposed.  It  is  not, 
however,  useless  to  vegetation,  since  it  is  a  well-known 
fact,  that  well-dried  seeds  may  be  preserved  from  germi- 
nation though  brought  in  free  contact  with  the  air. 

Water  appears  to  me  to  produce  two  undeniable  effects 
in  germination.  In  the  first  place  it  penetrates  the  cover- 
ing of  the  seed  to  deposit  within  it  the  oxygen  of  the  air 
which  it  holds  in  solution,  in  order  to  produce  the  forma- 
tion of  the  first  portion  of  carbonic  acid ;  and  in  the 
second,  it  opens  a  free  access  by  which  the  air  can  enter 
into  the  grain,  and  act  upon  it  in  the  manner  already 
pointed  out. 

From  what  I  have  already  stated,  it  follows,  that  ger- 
mination cannot  well  be  carried  on,  unless  the  atmo- 
spheric air  has  access  to  the  seed,  which  cannot  be  the 
ease  if  the  seed  be  buried  too  deeply  in  the  ground,  or  if 
it  be  sown  in  a  compact  soil  and  closely  covered  over. 

It  likewise  follows,  from  these  principles,  that  when  the 


GERMINATION. 


79 


earth  remains  a  long  time  covered  with  standing  water, 
the  seeds  must  decay,  and  also,  that  a  seed  placed  in  dry 
earth  cannot  germinate  unless  it  be  moistened. 

The  impossibility  of  a  seed's  germinating,  when  too 
deeply  buried  in  the  ground,  explains  why  we  sometimes 
see,  after  deep  tilling,  plants  making  their  appearance,  of 
the  same  kind  as  those  which  had  been  cultivated  upon 
the  soil  several  years  before.  The  state  of  the  earth  as  it 
regards  moisture,  at  the  time  of  sowing,  furnishes  a  reason, 
independent  of  the  action  of  heat,  why  seeds  are  a  longer 
or  shorter  time  in  sprouting. 

Seeds  do  not  germinate  in  pure  carbonic  acid.  Mixed 
with  atmospheric  air  this  gas  retards  the  process  of  ger- 
mination ;  but  it  may  be  hastened  by  absorbing  the  car- 
bonic acid  evolved  by  the  seeds,  by  means  of  lime  or 
alkalies. 

During  the  first  stages  of  vegetation  the  feeble  plant 
rejects  those  other  aliments  which,  as  it  advances  in 
strength,  become  the  principal  agents  in  its  nutrition. 

Germination  takes  place  in  the  same  space  of  time  in 
darkness  as  in  light.  But  M.  de  Saussure  has  observed, 
that,  after  the  process  of  germination  was  completed,  the 
developement  of  plants  was  more  rapid  and  perfect  in  the 
light  than  in  obscurity. 

Thus  we  see,  that,  in  the  germination  of  seeds,  every 
thing  may  be  reduced  to  the  following  facts. 

Water,  or  moisture,  swells  the  seed,  and  the  oxygen 
contained  in  that  liquid  subtracts  from  the  seed  the 
carbon  which  is  its  principal  constituent. 

The  swelling  of  the  seed  by  water  facilitates  the  intro- 
duction of  atmospheric  air  into  the  interior  of  the  grain, 
where  its  oxygen  can  combine  more  readily  with  the 
carbon  for  the  formation  of  carbonic  acid,  which  is  dis- 
engaged under  the  form  of  a  gas. 

The  heat  necessary  for  germination  facilitates  the  ac- 
tion of  the  oxygen  and  the  volatilization  of  the  carbonic 
acid  gas,  at  the  same  time  that  it  excites  the  germ  and 
stimulates  its  developement. 

The  subtraction  of  a  portion  of  their  carbon  changes 
the  state  and  the  nature  of  seeds.  The  mucilage  and  the 
starch,  of  which  they  are  almost  entirely  composed,  by 
parting  with  a  portion  of  their  carbon,  pass  to  the  state  of 
sweetish,  milky  substances,  containing  sugar,  which  is 
the  first  nourishment  of  the  embryo  plants. 


80  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

CHAPTER  V. 

OP    THE    NOURISHMENT    OF     PLANTS. 

As  soon  as  a  plant  begins  to  unfold  its  leaves,  and  to 
fasten  its  roots  in  the  earth,  it  is  nourished  by  new 
aliments,  which  it  receives  from  the  air  and  the  soil  by 
which  it  is  surrounded. 

The  organs,  which  convey  to  the  plant  its  new  nourish- 
ment, are  principally  the  leaves  and  the  roots.  The  leaves 
absorb  some  of  the  gases  contained  in  the  air;  and  the 
roots  draw  in,  with  the  water  containing  them,  the  juices 
and  salts  which  are  mixed  with  the  soil ;  and  the  gases 
which  are  developed  in  it  are  imbibed  by  them  through 
the  medium  either  of  air  or  water. 


ARTICLE   I. 

The  Influence  of  Carbonic  Acid  upon  Nutrition. 

Plants  absorb  carbonic  acid  from  water  and  the  air. 
In  the  light  they  decompose  it,  and  assimilate  the  carbon 
and  a  part  of  the  oxygen. 

A  small  portion  of  carbonic  acid  added  to  that  existing 
in  the  atmosphere  is  favorable  to  vegetation ;  too  large  a 
quantity  is  hurtful. 

The  presence  of  this  gas  is  indispensable  to  vegetation, 
but  the  want  of  it  is  not  equally  great  during  all  periods 
of  the  growth  of  plants.  A  very  young  plant,  of  which 
the  leaves  and  roots  have  just  begun  to  be  developed, 
languishes  if  watered  with  water  containing  the  acid. 
When  it  has  acquired  some  strength  and  size,  its  growth 
and  vigor  are  increased  by  the  operation.  Sennebier  has 
observed,  that  young  leaves  decomposed,  from  an  equal 
volume  of  air  during  the  same  time,  less  carbonic  acid 
than  leaves  of  full  size. 

Vegetation  can  generally  be  accelerated  by  mixing  with 
the  atmospheric  air  iV  O'*  iV  ^^  carbonic  acid  gas ;  but 
this  addition  is  not  favorable  unless  the  plants  are  ex- 
posed to  the  sun..  In  the  shade  any  addition  whatever  is 
injurious. 


INFLUENCE    OF    CARBONIC    ACID    UPON    NUTRITION.       81 

The  effects  produced  by  mould,  and  many  other  sub- 
stances which  are  employed  to  promote  vegetation,  are  in 
a  great  part  owing  to  the  carbonic  acid  gas,  which  they 
are  continually  transmitting  directly  to  the  plant  by  its 
roots,  or  throwing  out  into  the  atmosphere,  whence  it  is 
imbibed  by  the  leaves. 

The  power  of  absorbing  carbonic  acid,  and  of  decom- 
posing it,  resides  principally  in  the  leaves  ;  and  the  decom- 
position is  very  active  when  they  are  exposed  to  the  sun, 
in  which  case  they  give  out  to  the  atmosphere  a  large 
quantity  of  oxygen  combined  with  a  little  azote. 

According  to  the  experiments  of  M.  de  Saussure,  plants 
retain  a  small  portion  of  the  oxygen  arising  from  the  de- 
composition of  carbonic  acid,  and  throw  out  the  rest  into 
the  atmosphere.  The  rapidity  with  which  the  decompo- 
sition of  carbonic  acid  is  carried  on,  is  in  proportion  to 
the  brilliancy  of  the  sun's  rays,  and  to  the  greenness  and 
freshness  of  the  leaves.  It  however  appears,  that  decom- 
position can  be  performed  in  the  shade,  though  not  very 
actively  ;  since  Sennebier  observed,  that  leaves  which  un- 
folded in  the  dark  were  sensibly  tinged  with  green,  which 
he  attributes  to  their  decomposition  of  carbonic  acid. 

I  will  here  mention  an  observation  which  I  made,  a  long 
time  since,  in  the  coal  mines  of  Bousquet,  in  the  depart- 
ment of  Beziers. 

The  pieces  of  wood  which  support  the  roof  of  the  long 
gallery  which  conducts  to  the  beds  of  coal,  were  loaded 
with  that  species  of  mushroom  which  usually  fixes  itself 
upon  the  trunks  of  old  trees  ;  the  entrance  of  the  gallery 
is  very  light,  but  the  light  gradually  diminishes  till  it 
is  lost  in  total  darkness.  I  was  much  struck,  in  pass- 
ing through  this  gallery,  with  the  different  appearances 
presented  by  the  mushrooms  in  the  various  degrees  of 
light ;  those  at  the  entrance  were  yellow,  and  their  texture 
so  compact  that  they  could  hardly  be  broken  by  thehiand. 
As  I  advanced,  the  reddish  yellow  color  grew  gradually 
fainter,  and  the  texture  of  the  plants  more  soft  and  spongy, 
till  at  the  bottom  of  the  gallery,  where  a  ray  of  daylight 
never  penetrates,  I  found  the  mushrooms,  though  as  large 
as  those  at  the  entrance,  perfectly  white,  and  nearly  with- 
out consistency,  so  much  so,  that  upon  pressing  them  with 
the  hand,  they  were  found  to  yield  much  liquid,  and  but 
little  fibrous  matter.  I  filled  several  bottles  with  these, 
and  took  in  my  hands  some  of  those  from  the  middle  and 


82  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

entrance  of  the  gallery.  A  comparative  analysis  of  these 
various  portions  afforded  me,  from  those  which  grew  at  the 
bottom  of  the  gallery,  only  water  saturated  with  carbonic 
acid,  a  small  quantity  of  mucilage,  and  a  little  parenchy- 
mous  fibre  swimming  in  the  liquid.  The  proportion  of 
acid  was  much  less,  and  that  of  ligneous  fibre  more  con- 
siderable, in  the  mushrooms  plucked  from  the  middle  and 
entrance  of  the  gallery,  particularly  in  the  last.  Those 
from  the  dark  part  of  the  gallery  contained  only  the  ele- 
ments of  nutrition  not  elaborated ;  whilst  in  the  other,  the 
process  of  assimilation  was  carried  on  more  or  less  per- 
fectly, in  proportion  as  light  and  atmospheric  air  had 
access  to  them  to  facilitate  vegetation ;  otherwise,  as  car- 
bonic acid  was  most  abundant  in  those  plants  which  grew 
in  darkness,  their  texture  ought  to  have  been  the  most 
thoroughly  impregnated  with  it. 


ARTICLE  II. 

The   Influence  of   Oxygen    Gas   upon   Nutrition. 

Healthy  leaves  absorb  oxygen  gas  during  the  night,  but 
the  phenomena  which  they  present  vary  according  to  the 
nature  of  the  plant.  Those  of  the  oak,  the  horse-chestnut, 
the  false  acacia,  &c.,  absorb  oxygen  and  evolve  a  less 
volume  of  carbonic  acid  than  they  consume  of  oxygen. 
The  leaves  of  fleshy  plants  diminish  the  volume  of  air  by 
absorbing  from  it  oxygen,  without  which  they  sensibly 
give  out  carbonic  acid. 

The  quantity  of  oxygen  absorbed  by  plants  is  in  propor- 
tion to  their  state  of  vigor.  It  is  likewise  regulated  by 
temperature  ;  being  greater  at  88°  than  at  55°  or  at  66° 
Fahrenheit. 

When  plants  remain  several  nights  under  receivers  filled 
with  atmospheric  air,  the  leaves  continue,  though  slowly, 
to  absorb  oxygen,  with  which  they  are  saturated  as  soon 
as  they  contain  1^  their  volume.  When  the  leaves  are 
saturated  with  oxygen  they  begin  to  form  carbonic  acid, 
by  combining  their  carbon  with  the  oxygen  of  the  atmo- 
sphere, without  at  the  same  time  changing  its  volume,  as 
they  never  employ,  for  the  formation  of  this  acid,  all  the 


INFLUENCE    OF    OXYGEN    GAS    UPON    NUTRITION.  83 

oxygen  which  they  can  absorb.  The  oxygen  absorbed  by 
leaves  enters  into  a  state  of  combination  in  them ;  the  oxy- 
gen which  can  be  disengaged  from  them,  in  a  vacuum,  by 
means  of  heat,  amounts  to  only  ^^  of  the  volume  absorbed ; 
the  gas  thus  extracted  is  not  pure,  but  consists  of  azote, 
carbonic  acid,  and  oxygen. 

It  is  very  probable  that  the  oxygen  absorbed  by  plants 
growing  in  darkness,  combines  with  their  carbon  to  form 
carbonic  acid  ;  this  remains  in  solution  in  their  juices,  till 
the  sun  effects  its  decomposition,  when  the  oxygen  is 
thrown  out  into  the  air  by  the  transpiration  of  the  leaves, 
whilst  the  carbon  enters  into  the  composition  of  the 
plants. 

Plants  can  unfold  only  in  an  atmosphere  containing 
oxygen  ;  nevertheless,  they  thrive  less  in  the  shade  in  pure 
oxygen,  than  if  it  be  combined  with  other  gases,  as  azote 
and  carbonic  acid. 

The  leaves  of  different  plants  do  not  consume  in  the 
shade  the  same  quantity  of  oxygen.  Those  of  fleshy  plants 
absorb  but  little,  which  they  retain  obstinately ;  and  dis- 
engage a  still  less  quantity  of  carbonic  acid.  As  these 
plants  preserve  better  than  others  their  carbon,  and  require 
but  a  small  quantity  of  oxygen,  they  can  live  in  soils  of 
but  little  fertility  :  they  will  •flourish  upon  heights  where 
the  air  is  much  rarefied,  and  upon  arid  sands. 

The  leaves  of  those  trees  which  are  naked  during  the 
winter,  are,  in  general,  those  which  absorb  the  most  oxy- 
gen, and  contain  the  most  carbon.  Not  only  do  these 
plants  prepare  all  the  juices  which  are  essential  to  vegeta- 
tion, and  to  the  formation  of  fruits ;  but  after  having  ful- 
filled these  functions,  they  continue  to  extract,  from  the 
earth  and  air,  the  principles  of  their  nourishment ;  these 
they  elaborate  and  deposit  between  the  bark  and  the  wood, 
to  serve  for  their  first  aliment  at  the  return  of  spring,  till 
the  developement  of  the  leaves  and  the  excitement  of  the 
roots  by  heat,  can  provide  for  their  nourishment  by  the 
absorption  of  foreign  substances.  The  experiments  of 
Mr.  Knight  have  established  this  theory. 

This  phenomenon  in  vegetation  bears  a  close  resem- 
blance to  that  which  we  observe  to  take  place  in  the 
greatest  number  of  insects,  in  some  birds,  and  in  many 
quadrupeds ;  which  become  torpid  during  the  winter,  and 
are  nourished,  whilst  in  that  state,  by  the  fat  deposited  in 
their  cellular  membranes  during  the  autumn. 


84  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Plants  growing  upon  marshes  and  bogs,  and  conse- 
quently surrounded  the  greater  part  of  the  time  by  an 
atmosphere  of  vapor,  consume  less  oxygen  gas  than  most 
other  herbaceous  plants.  In  general,  the  quantity  of  oxy- 
gen absorbed  by  plants,  is  in  proportion  to  the  fertility  of 
the  soil  in  which  they  grow,  and  to  the  quantity  of  gas 
contained  in  the  air  by  which  they  are  surrounded. 
These  inferences  have  been  drawn  from  the  results  of  nu- 
merous experiments  made  by  M.  de  Saussure. 

Healthy  roots,  separated  from  their  stems,  and  placed 
under  a  bell-glass,  diminish  the  volume  of  atmospheric  air, 
and  form  carbonic  acid  with  the  surrounding  oxygen :  in 
this  case  they  never  absorb  a  volume  of  oxygen  greater 
than  their  own.  If  a  root,  thus  saturated,  be  placed  under 
another  receiver  filled  with  common  air,  it  will  form  car- 
bonic acid  without  changing  the  volume  of  the  air ;  but 
if  it  be  then  exposed  to  the  open  air,  it  will  absorb  a  quan- 
tity of  oxygen  gas  nearly  equal  to  its  volume,  as  when  it 
was  enclosed  under  the  first  receiver ;  which  proves  that 
free  atmospheric  air  can  take  from  roots  the  carbonic  acid 
which  they  form. 

It  is  plain,  then,  that  roots  exercise  the  same  action,  in 
regard  to  oxygen,  that  leaves  do,  though  they  absorb  less 
of  it.  The  only  important  difference  is,  that  the  roots  do 
not  decompose  the  carbonic  acid  ;  this  office  appears  to  be 
confined  to  the  leaves,  to  which  the  acid  is  transported,  to 
be  decomposed  by  the  solar  rays. 

When  the  root  is  not  separated  from  the  stem,  the  re- 
sults differ  from  the  above  ;  in  the  last  instance,  the  root 
absorbs  more  than  once  its  volume  of  oxygen  ;  the  reason 
of  this  is  very  simple  :  the  carbonic  acid,  as  soon  as  it  is 
formed,  is  dissolved  in  the  juices  of  the  root,  passes  from 
that  into  the  stem,  thence  into  the  leaves,  in  which  its  de- 
composition is  principally  performed  ;  so  that  the  root  parts 
with  the  carbonic  acid  as  soon  as  it  is  formed,  and,  though 
it  is  constantly  producing,  is  never  surcharged  with  it. 

Not  only  do  the  roots  absorb  oxygen  from  the  atmospher- 
ic air  which  penetrates  to  them,  but  they  disengage  that 
which  always  exists  in  the  water  by  which  they  are  moist- 
ened. This  leads  to  the  explanation  of  a  fact  which  I 
have  often  observed.  When  the  roots  of  almost  any  tree 
have  become  surrounded  by  stagnant  water,  enclosed  be- 
neath the  soil,  and  secluded  from  the  access  of  atmospheric 
air,  the  tree  soon  begins  to  languish,  and  the  leaves  to  turn 


iNPLUENCE    OF    AIR    UPON    FRUITS.  85 

yellow  and  die.  In  this  case  it  appears  that  the  water  has 
become  exhausted  of  oxygen,  without  having  the  power  of 
renewing  it,  and  when  that  is  no  longer  present  for  the 
roots  to  absorb,  they  decay  ;  whilst,  if  the  root  were  sup- 
plied with  flowing  water,  it  would  be  constantly  receiving 
fresh  supplies  of  oxygen  for  the  formation  of  carbonic  acid, 
which  furnishes  the  principal  nutrition  of«the  plant. 

The  wood,  the  parenchyma,  the  petals,  and,  in  general, 
all  those  parts  of  plants  which  are  not  green,  do  not  inhale 
and  exhale,  alternately  during  the  day  and  night,  the  oxy- 
gen gas  which  surrounds  them  ;  but  they  absorb  a  small 
quantity,  which  combines  with  their  carbon,  and  remains 
in  solution  in  their  juices,  till  it  is  conveyed  to  the  leaves, 
when  it  is  decomposed  by  the  rays  of  the  sun.  According 
to  this  it  appears,  that  carbon,  which  forms  one  of  the 
most  abundant  principles  of  the  juices  and  other  manures 
which  are  furnished  to  plants  to  supply  them  with  nourish- 
ment, cannot  be  assimilated  by  them,  unless  it  be  com- 
bined with  oxygen,  and  form  carbonic  acid.  In  this  state 
it  is  thrown  into  the  atmosphere,  whence  it  is  gradually 
absorbed  by  the  leaves,  and  decomposed  by  them.  One 
experiment,  which  seems  to  establish  this  opinion,  is  that 
of  absorbing,  by  means  of  lime  or  the  caustic  alkalies,  the 
carbonic  acid,  as  fast  as  it  is  transpired  by  the  leaves,  the 
consequence  of  which  is  the  death  of  the  plant 


ARTICLE  in. 

The  Influence  of  Air  upon  Fruits, 

M.  Berard,  in  his  experiments  on  the  effect  of  air  upon 
fruits,  placed  green  fruits  of  various  kinds  in  well-corked 
flasks,  or  under  bell-glasses  inverted  over  mercury,  and  ex- 
posed them  to  a  strong  light.  After  the  fruit  had  remained 
within  these  glasses  twenty-four  hours,  an  analysis  of  the 
air,  of  which  the  volume  was  from  seven  to  eight  times 
greater  than  that  of  the  fruit,  always  presented  him  with 
the  following  results. 


86  CHYMISTRY    APPLIED    TO    AGRICULTURE, 

Carbonic  acid 4 

Oxygen 16.8 

Azote 79.2 


100 

In  every  instance,  a  portion  of  oxygen  had  disappeared, 
and  bad  been  replaced  by  a  nearly  equal  quantity  of  car- 
bonic acid.  The  quantity  of  carbonic  acid  given  out,  is 
often  found  to  be  a  little  less  than  that  of  the  oxygen  ab- 
sorbed. By  diminishing  the  quantity  of  air  in  which  the 
fruits  are  exposed,  the  oxygen  may  be  almost  wholly  ab- 
sorbed. Experiments  made  with  glasses,  of  which  the 
fruits  occupied  one  third  of  the  capacity,  presented  the 
following  results. 

Carbonic  acid 18.52 

Oxygen 1.96 

Azote        79.52 


100 

It  appears  to  be  proved  by  these  experiments,  that  fruits 
exposed  to  the  action  of  air  in  a  well-lighted  place,  and 
under  the  successive  influences  of  day  and  night,  absorb 
oxygen,  which  combines  with  the  carbon  of  the  fruits,  and 
forms  a  volume  of  carbonic  acid  nearly  equal  to  that  of  the 
oxygen  imbibed. 

The  same  changes  took  place  when  the  apparatus  was 
exposed  to  the  rays  of  the  sun,  but  with  this  difference, 
that  the  decomposition  of  the  air  was  more  prompt  and 
more  complete  in  the  direct  rays,  of  the  sun,  than  merely 
in  daylight,  or  in  the  darkness  of  night. 

Some  almonds  exposed  to  the  sun  from  nine  o'clock  in 
the  morning  till  four  in  the  afternoon,  changed  the  air  of  a 
bell-glass  as  follows  : 

Carbonic  acid 15.74 

Oxygen 5.65 

Azote        78.61 


100 

In  this  instance  it  appears,  that,  besides  the  carbonic  acid 
formed  by  the  union  of  the  oxygen  of  the  atmosphere  with 
the  carbon  of  the  fruit,  the  fruit  itself  furnished  a  small 
quantity ;  whence  M.  Berard  concluded,  that  fruits  affect 
the  air  very  differently  from  flowers.     Instead  of  changing, 


INFLUENCE    OF    AIR   UPON    FRUITS.  87 

as  the  leaves  do,  when  acted  upon  by  the  solar  rays,  the 
carbonic  acid  of  the  atmosphere  into  carbon  and  oxygen  ; 
the  fruits  unite  the  oxygen  of  the  atmosphere  with  their 
own  carbon,  for  the  formation  of  carbonic  acid  ;  so  that, 
in  the  sun,  as  in  the  shade,  they  absorb  oxygen,  and  trans- 
pire carbonic  acid. 

M.  Berard  obtained  the  same  rosults  when  his  experi- 
ments were  performed  upon  fruits  still  adhering  to  the  tree, 
and  which  were  in  full  vegetation. 

The  ripening  of  fruits  appeared  to  M.  Berard  to  be  per- 
formed by  the  subtraction  of  their  carbon,  through  the 
assistance  of  the  oxygen  of  the  air  by  which  they  were 
surrounded.  When  this  subtraction  is  in  any  way  pre- 
vented, the  fruit  withers  and  dies. 

When  a  vacuum  is  produced  in  receivers  containing  the 
fruits;  or  when  these  fruits  are  surrounded  by  an  atmo- 
sphere of  hydrogen,  of  azote,  or  of  carbonic  acid,  they 
disengage  at  firsf  a  flmall  quantity  of  carbonic  acid,  bat 
the  quantity  of  it  diminishes  sensibly,  and  ceases  altogether 
towards  the  third  or  fourth  day. 

In  every  instance,  green  fruits  remained  a  long  time 
without  undergoing  any  change ;  they  made  no  advance 
towards  ripening,  but  continued  stationary ;  resuming, 
however,  their  natural  action,  when,  at  the  end  of  several 
days,  they  were  placed  in  a  situation  in  which  they  could 
absorb  oxygen,  and  transpire  carbonic  acid. 

When  fruits  are  ripe  they  continue  to  absorb  oxygen, 
and  to  form  carbonic  acid  by  the  union  of  it  with  a  portion 
of  their  carbon  ;  they  likewise  furnish  a  great  quantity  of 
this  acid,  which  is  produced  by  the  combination  of  their 
own  elements. 

The  observations  made  by  M.  Berard  upon  fruits,  at 
different  stages  of  maturity,  show  that  the  same  principles 
are  found  in  them  at  various  periods,  but  combined  in 
unlike  proportions.  I  will  here  cite  only  one  of  these 
analyses. 

Apricots,  very  green.    More  advanced.    Ripe. 

Animal  matter    ....    0.76  0.34  0.17 

Green  coloring  matter  .  .  0.04  0.03  0.10 

Woody  substance   .    .    .    3.61  2.53  1.86 

Oum 410  4.47  5.12 

Sugar       .     .     .   some  appearances.         8.64  16.48 

Malic  acid   .....    2.10  2.30  1.80 

Lime a  little.  a  little,  a  little. 

Water 89.39  84.49  47.84 


88  CHYMISTRY    APPLIEU    TO    AGRICtTLTURE. 

Cherries,  currants,  prunes,  peaches,  &c,,  analyzed,  both- 
when  green  and  when  ripe,  presented  the  same  results,, 
with  some  slight  difference  in  the  products. 

By  the  process  of  ripening  the  animal  matter,  woody 
substances,  malic  acid,  and  water  are  diminished,  whilst 
the  sugar  is  considerably  increased.  This  last  substance, 
when  extracted  from  grapes,  figs,  and  peaches,  fully  ripe, 
may  be  partially  crystallized;  whilst  that  from  apples, 
pears,  currants,  cherries,  apricots,  and  prunes,  remains 
liquid  and  uncrystallizable. 

When  green  fruits,  fully  grown  and  ready  for  ripening, 
are  placed  in  an  atmosphere  deprived  of  oxygen,  the  pro- 
cess of  ripening  does  not  go  on ;  it  is,^  however,  only  sus^ 
pended,  and  will  commence  when  the  fruit  is  replaced  in 
a  situation  where  it  can  obtain  oxygen  ;  unless  it  has  been 
kept  too  long  in  the  dis-oxygenated  air. 

After  ripening,  fruit  undergoes  another  alteration,  which 
changes  its  nature  ;  it  becomes  mouldy  or  rotten,  and  in 
this  state  gives  out  great  quantities  of  carbonic  acid.  The 
carbon  is  principally  furnished  by  the  woody  portion,  which 
turns  brown,  and  by  the  sugar,  the  proportion  of  which  is 
gradually  diminished  till  it  finally  disappears  ;  whilst  the; 
oxygen  can  reasonably  be  attributed  only  to  the  decompo- 
sition of  the  water.  I  am  the  more  inclined  to  believe  this 
assertion,  because  it  may  be  observed  every  day,,  that  when 
fruits  are  fermenting',  or  decaying  in  heaps,  a  peculiar  odor 
may  easily  be  distinguished  in  the  surrounding  atmosphere, 
approaching  to  that  of  some  gaseous  combinations,  es- 
pecially that  of  hydrogen  with  carbon. 

M.  de  Saussure,  who  repeated  the  experiments  of  M. 
Berard  upon  fruits,  has  deduced  from  them  consequences 
somewhat  different ;  he  believes  this  to  arise  from  M. 
Berard's  having  enclosed  his  fruits  in  jars  containing  only 
six  or  eight  times  their  volume  of  air;  the  almost  imme- 
diate contact  of  the  sides  of  the  receivers,  heated  by  the 
sun,  must  necessarily  have  produced  a  change  in  the  fruits, 
by  occasioning  the  commencement  of  decomposition. 

The  result  of  the  experiments  of  M.  de  Saussure  leads 
to  the  conclusion,  that  green  fruits  exercise  the  same  ac- 
tion upon  the  air  as  the  leaves  do,  though  with  less  in- 
tensity. Like  the  leaves,  green  fruits  absorb  oxygen 
during  the  night,  and  give  out  carbonic  acid,  of  which 
they  again  absorb  a  part.  Fruits  transpire  oxygen  in  the 
sun  ;  when  very  green  they  consume  more  oxygen  in  the 
dark,  than  when  they  approach  to  maturity. 


INFLUENCE    OP    WATER   UPON   NUTRITION.  89 

The  experiments  of  M.  de  Saussure  have  always  been 
made  upon  volumes  of  air,  exceeding  from  thirty  to  forty 
times  those  of  the  fruits ;  and  by  this  means  the  heating 
action  of  the  sun  was  much  diminished. 

The  results  of  the  experiments  of  M.  Berard  are  all 
applicable  to  the  ripening  of  fruits,  which  was  the  par- 
ticular object  of  his  attention ;  whilst  those  of  M.  de 
Saussure  relate  chiefly  to  their  growth.  The  first  con- 
siders the  changes  they  undergo  when  detached  from  the 
tree  ;  and  if  he  sometimes  performed  his  experiments  upon 
green  fruits,  their  action  under  his  small  receivers  was 
like  that  of  dead  bodies.  The  second  analyzed  the  phe- 
nomena of  their  growth;  and  it  is  not  astonishing,  that 
the  two  should  have  obtained  different  results. 


ARTICLE   IV. 

The  Influence  of  Water  upon  Nutrition. 

Water  influences  vegetation  not  only  by  the  nutritive 
principles  furnished  to  plants  by  its  decomposition,  but  by 
means  wholly  physical,  and  which  we  shall  first  consider. 

The  first  effect  of  water  upon  a  soil  appropriated  to 
vegetation  is,  to  moisten  and  divide  the  earth,  and  conse- 
quently to  favor  the  extension  of  roots,  the  introduction  of 
air,  and  the  developement  of  seeds. 

The  second  is  that  of  conveying  to  the  seed  the  first 
aliment  required  by  it,  oxygen,  which  that  liquid  always 
holds  in  solution  in  a  greater  or  less  degree,  and  which  is, 
as  I  have  already  observed,  the  principal  agent  in  germi- 
nation. 

The  third  office  performed  by  water  is  that  of  dividing 
the  manure  applied  to  the  soil,  of  dissolving  some  portions 
of  it,  and  conveying  them  to  the  organs  of  the  plants  in  a 
state  fitted  for  their  digestion  and  nourishment. 

All  kinds  of  water  are  not  equally  suitable  for  this  pur- 
pose; rain  water,  which  is  the  purest  and  contains  the 
most  air  of  any,  is  also  the  best  for  supplying  the  wants  of 
plants.  Generally  speaking,  those  streams  which  have 
their  rise  in  granitic  or  primitive  calcareous  mountains, 
are  favorable  to  vegetation  ;  but  it  is  necessary  that  they 
8* 


90  CHYMrSTKY    APPLIED    Ta  AGRICULTURE. 

should  flow  through  soils  free  from  metallic  salts  or  earths  ; 
and  that  they  should  have  traversed,  before  being  used  in 
agriculture^  a  sufficient  space  to  have  become  impregnated 
u^ith  a  due  portion  of  atmospheric  air. 

Streams  may  not  be  pure,  and  yet  may  be  very  serviceable 
for  watering  the  soil,  especially  if  they  carry,  or  hold  in 
solution,  certain  salts  favorable  to  plants,  and  some  animal 
or  vegetable  substances.  In  this  case  they  possess  double 
virtue,  and  produce  double  effect. 

Waters  may  be  divided  into  three  classes ;  the  first  com- 
prehending those  that  are  charged  with  animal  matter; 
the  second,  those  which  hold  in  solution  some  of  the  prin- 
ciples of  vegetables;  and  the  third,  the  pure  waters,  or 
those  which  contain  salts  in  but  small  quantities. 

The  waters  of  the  first  class  are  the  most  active ;  and 
amongst  them,  those  which  are  loaded  with  the  sweat  of 
wool,  or  with  the  ammoniacal  combinations  arising  fi-om 
the  fermentation  of  powdered  bones,  of  shavings  of  horn, 
or  fragments  of  wool,  hold  the  first  rank.  When  employed 
in  their  dry  state,  as  manures,  these  substances  produce 
their  effects  very  slowly,  but  exercise  a  much  more  ener- 
getic action  when,  during  decomposition  by  putrefaction, 
their  products  are  absorbed  by  water  as  fast  as  formed, 
and  immediately  conveyed  to  the  plants.  The  soft,  fleshy, 
or  liquid  portions  of  animal  substance  do  not  produce  so 
lasting  an  effect ;  their  decomposition  is  too  rapid  for  their 
action  to  be  continued  for  any  length  of  time. 

The  waters  of  the  second  class,  those  that  are  charged 
with  some  of  the  products  of  vegetation,  either  natural  or 
arising  from  decomposition,  form  very  good  manures. 

When  plants  have  yielded  to  water  all  their  soluble  por- 
tions, the  subsequent  decomposition  of  their  insoluble 
fibres  furnishes  new  soluble  products,  which  serve  for 
nourishment ;  water  imbibes  these  as  fast  as  they  are 
formed,  and  transmits  them  to  the  plants  with  which  it 
comes  in  contact.  In  this  manner  dead  plants  supply 
food  to  the  living,  and  all  the  elements  composing  the  first 
are  found  differently  combined  in  the  last. 

When  natural  vegetable  products,  or  those  arising  from 
decomposition,  are  mixed  with,  or  dissolved  in  urine  or 
the  other  animal  fluids  which  are  charged  with  salts,  the 
effect  upon  vegetation  is  much  increased,  because,  in  ad- 
dition to  exciting  the  digestive  organs  of  plants,  these  salts 
dissolve  some  substances  which  could  not  in  their  original 


INFLUENCE    OP   WATER    UPON    NUTRITION.  91 

State  penetrate  into  these  organs.  It  is  for  this  reason 
that  cakes  of  rape  seed,  wild  mustard,  and  nuts,  used  in 
the  manner  mentioned  above,  afford  the  best  manure 
known. 

The  waters  constituting  the  third  class,  hold  in  solution 
some  salts;  these  salts  may  be  considered  as  performing 
several  offices  in  the  act  of  vegetation;  they  stimulate  the 
vitality  of  plants,  and  increase  the  activity  of  their  powers ; 
they  produce,  in  fact,  upon  plants,  the  same  effects  as  those 
produced  upon  the  human  body  by  the  use  of  such  condi- 
ments as  marine  salt,  and  salt-petre.  Salts  of  the  same 
nature  as  those  contained  in  waters  of  the  third  class,  al- 
ways produce  good  effects  upon  the  soil  to  which  they  are 
applied,  either  by  sprinkling  the  ground  with  them,  or  com- 
bining them  with  barn-yard  manure. 

Though  these  salts  are  useful  to  vegetation,  it  is  neces- 
sary to  guard  against  using  them  in  excessive  portions,  as 
they  then  dry  up  and  destroy  the  plants.  Lands  which 
have  been  long  overflowed  by  the  sea,  refuse  to  yield  any 
thing  to  cultivation  till  they  have,  by  the  repeated  action  of 
fresh  water,  been  freed  from  the  salt  with  which  they  had 
become  impregnated. 

Some  of  the  salts  that  are  conveyed  into  plants  by  water, 
exert  an  influence  over  them  independent  of  their  stimulat- 
ing power ;  being  decomposed  within  their  organs,  and 
serving,  by  the  assimilation  of  their  constituent  principles, 
as  nourishment  to  the  plants.  The  greater  part  of  the  salts 
derived  from  the  animal  or  vegetable  kingdoms,  are  of  this 
description. 

Having  considered  water  as  a  mechanical  power,  and  as 
a  vehicle  for  the  conveyance  of  food  to  plants,  it  remains 
for  me  to  make  known  its  direct  influence  upon  them. 

M.  de  Saussure  has  proved,  by  experiment,  that  plants 
decompose  water,  and  appropriate  to  their  own  uses  the 
hydrogen  and  the  oxygen  contained  in  it ;  but  this  assimila- 
tion is  very  trifling,  if  they  cannot  at  the  same  time  absorb 
carbonic  acid.  The  small  increase  of  weight  gained  by  a 
plant  in  an  atmosphere  containing  only  oxygen,  sufficiently 
verifies  this. 

Dead  plants  which  ferment  when  secluded  fi-om  oxygen, 
give  out  some  carbonic  acid ;  but  this  only  proves  the 
combination  between  the  carbon  and  oxygen  contained  in 
vegetable  products. 

Next  to  carbon,  the  most  abundant  principle  in  plants  is 


92  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

hydrogen  ;  which  appears  to  be  furnished,  in  a  great  meas- 
ure, by  their  power  of  decomposing  water.  Hydrogen  can 
be  obtained  from  plants  by  distillation,  but  in  the  decompo- 
sition of  dead  vegetables,  it  unites  either  with  the  oxygen 
of  the  air  to  form  water,  or  it  is  exhaled  in  union  with  car- 
bon as  carburetted  hydrogen. 


ARTICLE  V. 


Of  the   Effects  of  the  Nourishment   of  Plants  upon  the 
Soil 

It  appears  to  be  clearly  proved,  that  plants  imbibe  from 
water  and  the  atmosphere  only  carbon,  oxygen,  and  hydro- 
gen ;  but  analysis  shows  us  that,  independently  of  these 
principles  and  the  products  arising  from  their  combinations, 
plants  contain  azote  and  some  earthy  and  saline  substances, 
which  cannot  be  produced  by  either  of  the  three  elements 
mentioned  above.  It  remains  then  for  us  to  inquire,  in 
what  manner  these  substances  have  been  introduced  into 
plants. 

Azote,  which  is  found  in  the  albumen,  the  gelatine,  and 
the  green  coloring  matter,  is  not  sensibly  drawn  from  the 
atmosphere,  though  it  constitutes  f  of  it,  but  passes  in  with 
oxygen  in  the  water  imbibed  by  plants,  and,  like  that,  is 
separated  in  their  organs. 

The  earths  which  are  insoluble  in  water,  but  which  are 
mixed  with,  or  suspended  in  that  fluid,  are  not  absorbed  in 
large  quantities  by  the  pores  of  plants,  but  may  be  conveyed 
into  them  by  the  aid  of  some  chymical  agents,  as  the  acids, 
the  alkalies,  &c.  Besides,  if  we  observe  attentively,  we 
shall  find  that  these  substances  do  not  abound  in  plants ; 
and  we  can  easily  conceive,  that  the  little  they  do  contain, 
might,  in  a  state  of  extreme  division,  be  introduced  by 
water. 

There  are  some  plants  that  fasten  themselves  and  grow 
upon  the  most  barren  rocks,  deriving  from  the  surrounding 
air,  and  from  rains,  all  the  nourishment  required  by  them ; 
of  this  number  are  the  mosses,  the  lichens,  and  the  fleshy 
plants.  Their  growth  is  slow,  their  transpiration  almost 
nothing,  and  their  color  remains   nearly  the  same  all  the 


EFFECTS    OF    PLANTS    UPON    THE    SOIL.  93 

year  round ;  so  that  they  constantly  absorb  water  and  car- 
bonic acid,  and  assimilate  their  constituent  principles. 

The  soil  is  always  exhausted,  in  a  greater  or  less  degree, 
by  the  plants  it  produces ;  and  much  more  by  those  that  are 
annual,  than  by  those  that  are  perennial.  Air  and  water 
alone  do  not  afford  a  sufficient  degree  of  nourishment  to 
plants,  for  when  they  have  been  made  to  grow  in  well  washed 
sand,  watered  with  distilled  water,  though  they  have  flow- 
ered, their  fruits  did  not  arrive  at  maturity.  Experiments  to 
this  effect  have  been  made  by  Messrs.  Giobert,  Hassenfratz, 
de  Saussure,  &lc. 

Those  annual  plants  which  transpire  most,  generally 
exhaust  the  soil  in  the  greatest  degree.  Peas,  beans,  and 
buckwheat,  though  they  have  succulent  stalks,  exhaust  it 
least,  because  they  transpire  but  little. 

When  annual  plants  are  cut  at  the  time  of  flowering, 
they  do  not  exhaust  the  soil,  as  their  succulent  roots  furnish 
materials  for  replacing  the  loss  occasioned  by  their  growth  ; 
but  after  having  produced  their  fruits,  the  soil  derives  but 
little  advantage  from  the  dry  fibres  which  are  the  only  re- 
mains of  their  stalks  and  roots. 

During  fructification,  plants  absorb  but  little  nourish- 
ment from  the  soil ;  the  supply  necessary  to  the  formation 
of  the  seed  is  furnished  by  those  juices  which  already 
exist  in  the  roots  and  stalks,  and  this  occasions  them  to 
become  dry  and  exhausted,  so  that,  when  the  fruit  is  per- 
fected, the  roots  and  stalks  consist  only  of  woody  fibre. 
It  is  necessary  that  this  fact  should  be  known,  in  order 
that  too  late  mowing  of  meadows,  whether  natural  or  ar- 
tificial, may  be  avoided.  The  most  favorable  period  for 
cutting  grass  is  that  of  its  flowering ;  if  the  operation  be 
postponed  till  the  seed  is  formed,  two  great  disadvantages 
will  arise ;  the  first  is,  that  the  fodder  obtained  will  have 
parted  with  the  greater  portion  of  its  nutritive  qualities ;  and 
the  second,  that  the  plants,  having  fulfilled  all  the  laws  of 
their  nature,  by  providing  for  their  reproduction,  cannot 
flourish  again  with  vigor  during  the  same  year.  In  sup- 
port of  this  doctrine,  I  will  mention  one  well-known  fact, 
which  is,  that  meadows  mown  before  fructification  af- 
ford the  most  abundant  harvests,  and  the  greatest  num- 
ber of  them,  as  they  may  be  mown  several  times  in  a  year. 
The  perennial  plants  which  serve  as  fodder,  may  by  this 
means  be  preserved  for  several  years  in  a  state  of  repro- 
duction, but  if  mown  after  the  formation  of  seed,  the 
plants   are   weakened    and   the   reproduction    is   lessened. 


94  CHYMISTRY    APPLIED  TO    AGRICULTURE 

All  farmers  know,  that  when  they  subject  to  tillage  a  piece 
of  artificial  grass  land,  which  has  for  several  years  been 
constantly  mown  at  the  time  of  flowering,  it  will  yield 
^  several  harvests  without  any  dressing ;  but  if  the  grass  has 
been  left  to  go  to  seed,  it  will  be  necessary  to  supply  the 
earth  with  manure  before  it  will  yield  a  good  return.  As 
those  plants  that  are  cut  at  the  time  of  flowering  do  not 
exhaust  the  soil  so  much  as  those  that  remain  for  seed, 
the  belief  has  arisen  amongst  farmers,  that  before  the 
period  of  fructification,  they  are  nourished  by  the  con 
stituent  principles  of  the  surrounding  air  and  water ;  but 
that  during  the  time  of  the  formation  of  the  seed,  theii 
support  is  almost  wholly  derived  from  the  earth.  But  this 
opinion  will  not  hold  in  regard  to  all  plants ;  lettuce,  tur- 
nips, tobacco,  woad,  endive,  cabbages,  and  onions  exhaust 
the  soil  greatly,  though  they  are  gathered  before  producing 
seed.  Potatoes,  though  they  produce  but  few  seeds,  impov 
f  erish  land  more  than  almost  any  other  vegetable.  Plants 
raised  in  a  nursery,  and  afterwards  transplanted,  exhaust 
the  soil  in  which  they  spring,  more  than  the  one  in  which 
they  complete  their  growth. 

Thus  we  see,  that  during  the  whole  time  of  their  vege- 
tation, plants  derive  their  nourishment  from  the  air,  and 
from  the  substances  contained  in  the  earth ;  but  if  they  are 
mown  at  the  time  of  flowering,  they  leave  in  the  soil  their 
roots  and  portions  of  their  stalks,  which  restore  to  the  earth 
nearly  as  much  as  they  have  received  from  it ;  whilst,  it 
they  remain  uncut  till  they  have  completed  their  course, 
they  return  little  or  nothing  to  the  soil  to  compensate  it  for 
the  nourishment  they  have  received  from  it. 

It  is  well  known  to  farmers,  that  ploughing  in  a  green 
crop  of  any  kind  whatever,  prepares  the  soil  for  producing 
well  without  any  other  manure;  since,  by  this  process,  all 
that  the  soil  has  yielded  is  returned  to  it,  with  some  addi- 
tions, resulting  from  the  decomposed  principles  of  air  and 
water,  which  are  contained  in  the  plants. 

In  order  fully  to  understand  this  doctrine,  which  appears 
to  me  of  great  importance  to  agriculture,  it  is  necessary 
to  consider  the  successive  changes  which  take  place  in 
annual  plants  during  their  growth ;  first,  they  produce 
green  leaves,  which,  by  coming  in  contact  with  the  air, 
receive  from  it  the  principles  of  which  I  have  spoken; 
subsequently  the  stalks  increase  in  size  and  number,  and 
are  covered  with  numerous  leaves,  which  absorb  from  the 


EFFECTS    OF    PLANTS    UPON    THE    SOIL.  95 

atmosphere  a  degree  of  nourishment  suited  to  the  increasing 
wants  of  the  plants ;  the  strength,  fullness,  and  depth  of 
hue  of  the  leaves  and  the  stalks,  particularly  of  the  latter, 
increase  in  proportion  to  the  richness  of  the  soil. 

This  state  continues  till  after  the  period  of  flowering, 
when  a  change,  worthy  of  note,  takes  place  ;  the  roots  dry 
up,  the  stalks  wither  and  change  their  color;  and  when 
fructification  is  at  length  completed,  both  roots  and  stalks 
have  become  mere  skeletons,  which  answer  but  little  pur- 
pose either  for  nourishing  animals  or  manuring  earth. 
During  this  period  of  vegetation  what  becomes  of  the 
juices  that  were  so  abundant  in  the  roots  and  stalks? 
They  have  been  consumed  by  the  formation  of  the  seeds. 
It  is  undoubtedly  the  case  that  plants  still  continue  during 
fructification  to  absorb  some  portion  of  their  nourishment 
from  the  air  and  soil ;  and  this  assists  in  the  formation  of 
their  seeds  ;  but  by  far  the  greatest  share  of  the  formation 
of  these  is  owing  to  the  deposits  contained  in  the  organs  of 
the  plants. 

The  same  holds  true  of  perennial  plants ;  and  it  may  be 
observed,  that  when  a  tree  produces  fruit  too  abundantly  it 
becomes  exhausted  and  dried,  and  bears  only  that  which  is 
small  and  misshapen.  The  difference  between  annual  and 
perennial  plants  is,  that  the  former  die  as  soon  as  the  process 
of  fiructification  is  completed ;  whilst  the  latter  preserve 
their  leaves  green  and  their  roots  fresh,  for  the  purpose  of 
absorbing  new  portions  of  nourishment,  to  be  deposited  in 
their  vessels  for  food  when  the  returning  warmth  of  spring 
shall  cause  them  to  require  it. 

M.  Matthieu  de  Dombasle,  one  of  our  most  enlightened 
agriculturists,  has  confirmed  by  experiments  the  doctrine 
I  have  here  advanced.  On  the  26th  of  June,  1820,  at  the 
time  of  flowering,  he  selected,  within  a  small  space,  forty 
wheat  plants  of  equal  size  and  strength,  each  having  three 
stalks  bearing  heads ;  he  pulled  twenty  of  the  plants  with 
ajl  their  roots,  and  left  the  rest  to  complete  their  fructifica- 
tion. Having  carefully  freed  from  earth  the  roots  of 
those  he  had  taken  up,  he  cut  the  stalks  two  inches  above 
the  base,  and  dried  separately  the  roots,  and  the  stalks 
surmounted  by  their  heads. 

The  roots  and  the  portion  of  the  stalks  remaining  with 
them  weighed,  grains         657 

The  stalks,  heads,  and  leaves,  **  1946.5 


Total  2603.5 


96  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

On  the  28th  of  August,  the  time  of  harvest,  he  plucked 
up.  the  twenty  plants  which  had  been  left  for  seed,  separat- 
ing the  roots,  and  cutting  the  stalks  as  of  the  first ;  of  these 
the  weight  was  as  follows, 

Grains. 

Roots 419.53 

Straw,  husks,  and  beards       1318.75 
Grain 1025.69 


Total        2763.97 

During  these  two  months,  the  roots  and  the  portions  of 
stalks  adhering  to  them  had  lost  237.52 

The  stalks,  head,  and  leaves  had  lost        624.67 


Total  loss  862.19 

But  as  the  seed  weighed  1025.69  grains,  the  whole  had 
increased  in  weight  160.47  grains,  Troy.  From  this  exper- 
iment we  may  conclude,  that  the  juices  contained  in  plants, 
at  the  time  of  flowering,  contribute  to  the  formation  of  the 
grain  in  the  proportion  of  -^Tp^i.if,  and  that  the  excess  of 
the  weight  of  the  grain,  which  is  xWf  .4~f »  arises  from  the 
nourishment  which  the  plant  absorbs  from  the  air  or  soil, 
during  the  two  months  of  fructification. 

If  the  wheat  is  mown  when  in  blossom,  it  leaves  in  the 
earth,  to  be  converted  into  manure,  a  quarter  part  of  the 
weight  of  the  plant;  but  when  it  is  reaped  after  having 
come  to  maturity,  there  remains  only  one  seventh;  and 
this  last  residue  is  worthless  as  manure  in  comparison 
with  the  first;  this  contains  almost  nothing  but  carbon, 
whilst  that  is  rich  in  juices  and  in  decomposable  matter. 
Thus  we  see  that  those  plants  which  form  seeds  exhaust 
the  soil  most,  because  for  all  they  have  received  they  return 
nothing  but  their  dry  roots  and  stalks ;  whilst  those  that  are 
cut  when  green  give  back  with  their  roots  and  stalks  what 
they  have  drawn  from  the  soil,  and  a  part  of  that  which 
they  have  drawn  from  the  atmosphere. 

The  nutritive  principles  contained  in  the  soil  pass  into 
plants  only  in  a  state  of  solution,  or  of  extreme  division  in 
water.  Healthy  plants  absorb  from  preference  those  salts 
that  are  most  congenial  to  them ;  but  if  waters  be  charged 
with  salts  unsuited  to  their  natures,  they  absorb  the  fluid 
and  reject  the  salts  till  the  water  becomes  thickened  by 
them. 


EFFECTS  OF  PLANTS  UPON  THE  SOIL.         97 

There  are  some  salts  which  enter  naturally  into  the  com- 
position of  certain  plants ;  the  pellitory  and  nettle,  for 
instance,  which  grow  upon  the  borders  of  the  sea,  contain 
muriate  or  sulphate  of  soda  ;  these  vegetables,  transported 
into  other  soils,  afford  no  vestige  of  these  salts,  and  their 
growth  is  less  vigorous.  M.  le  Marquis  de  Bullion  has 
proved  that  the  turnsol,  raised  in  earth  containing  no  nitre, 
does  not,  upon  analysis,  afford  a  vestige  of  any  ;  but  that 
plants  of  the  same  kind,  raised  in  the  same  soil,  but  wa- 
tered with  a  solution  of  nitrate  of  potash,  are  charged  with 
that  salt. 

Generally  speaking,  a  superabundance  of  salts,  especially 
if  they  be  of  kinds  very  soluble  in  water,  injures  vegeta- 
tion :  this  is  particularly  the  case  when  the  salts  are  not 
such  as  enter  naturally  into  the  plants,  amongst  the  num- 
ber of  their  constituent  principles.  Salts  of  foreign  na- 
tures cannot  be  useful,  excepting  as  they  may  serve,  in 
very  small  quantities,  to  excite  and  stimulate  the  organs  of 
plants.  The  great  value  of  sulphate  of  lime  as  a  manure, 
is  owing  to  its  insolubility,  which  allows  water  to  contain 
but  a  very  small  portion  of  it  at  once;  so  that  it  passes 
into  plants  very  gradually,  and  thus  its  effects  are  pro- 
longed for  several  years ;  till,  as  I  have  before  observed, 
the  soil  is  exhausted  of  it. 

The  quantity  and  quality  of  the  salts  contained  in  plants 
may  be  ascertained  by  an  analysis  of  the  ashes  arising 
from  burning  them  in  a  dry  state.  It  may  not  be  useless 
to  mention  here  some  facts  which  may  throw  light  upon 
this  subject. 

Kirwan  and  Ruckers  have  proved,  that  an  equal  weight 
of  herbaceous  plants  furnishes  more  ashes  than  of  ligne- 
ous plants.  M.  Pertuis  has  found,  that  the  trunks  of  trees 
afford  less  ashes  than  the  branches,  and  these  last  less  than 
the  leaves.  Evergreens  yield  less  ashes  than  trees  and 
shrubs  that  shed  their  leaves  in  autumn.  On  the  other 
hand.  Hales  and  Bonnet  have  observed,  that  the  perspira- 
tion of  herbaceous  is  greater  than  that  of  ligneous  plants, 
and  that  that  of  evergreens  is  less  than  that  of  plants 
which  shed  their  foliage.  These  circumstances  may  ex- 
plain why  some  plants  afford  more  ashes  than  others.  The 
water  which  is  evaporated  by  transpiration  deposits  in  the 
cells  of  the  plant  the  salts  which  it  had  held  in  solution, 
and  is  replaced  by  a  new  quantity,  which  is  in  its  turn 
thrown  out,  leaving  behind  it  an  additional  portion  of 
9 


08  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

salts ;  so  that  those  plants,  and  those  portions  of  the  same' 
plant,  which  transpire  most,  must  necessarily  contain  the 
greatest  quantity  of  salts. 

The  salts  and  earths  contained  in  plants  are  of  the 
same  nature  as  those  existing  in  the  soil  in  which  they 
grow,  but  not,  according  to  analysis,  in  the  same  propor- 
tions; because  the  plant  absorbs  more  or  less  of  them  ac- 
cording to  its  own  nature  and  their  solubility.  It  cannot, 
however,  be  strictly  said,  that  all  the  salts  contained  in 
plants  existed  previously  in  the  soil,  as  some  neutral  salts 
are  evidently  formed  within  their  organs ;  such  are  those 
of  which  the  acid  is  known  to  us,  and  particularly  those 
that  contain  in  their  composition  a  vegetable  principle  :  of 
this  sort  are  the  acetates,  the  malates,  and  the  citrates. 
The  salts  do  not  exist  after  the  burning  of  the  plant,  be- 
eause  their  acid  is  decomposed  by  the  action  of  fire,  and 
there  remains  only  their  base,  which  is  usually  potash  or 
lime ;  but  an  analysis  of  the  plant  "  by  the  wet  way  "  gives 
proof  of  their  existence. 

It  is  even  possible  in  some  cases  to  follow  the  formation 
of  the  acid,  by  observing  the  progress  of  vegetation,  and 
the  changes  produced  in  its  products.  Of  this  I  will  men- 
tion one  example.  Beets  gathered  late  in  autumn,  in  the 
north  of  France,  do  not  yield  the  same  principles  as  those 
gathered  at  the  same  period  in  the  south  of  France  ;  the 
first  contain  sugar,  the  second  salt-petre.  According  to 
the  experiments  carefully  made  by  M.  Darracq  in  the  de- 
partment of  Landes,  the  beet  roots  of  the  south  yield  g,s 
much  sugar  in  the  month  of  August  and  the  earlier  part 
of  September,  as  those  of  the  north ;  this  sugar  then  is 
replaced  by  salt-petre,  of  which  the  acid  is  formed  during 
the  progress  of  vegetation.  It  has  been  observed,  that 
beets  containing  sugar  frequently  underwent  a  change 
during  the  winter,  by  which  the  sugar  entirely  disappeared, 
and  was  replaced  by  salt-petre  ;  in  this  case  we  can  almost 
follow  with  the  eye  the  process  of  decomposition.  The 
juice  of  beets  in  which  the  change  has  commenced,  when 
thrown  into  the  boilers,  becomes  covered  with  a  thick, 
white  foam,  which  gives  out  a  reddish  vapor  of  nitrous 
gas:  in  this  state  the  labor  of  extracting  sugar  becomes 
very  difficult ;  the  sugar  crystallizes  badly,  and  the  propor- 
tion of  molasses  is  very  great.  It  may  be  seen  clearly,  that 
in  this  state  oxygen  is  already  united  in  the  beets  with 
azote,  and  that  only  an  additional  portion,  which  would  be 


CHANGES   PRODUCED    BY    NOURISHMENT.  99 

gained  during  the  progress  of  change  in  the  roots,  is  want- 
ing for  the  formation  of  nitric  acid ;  this,  combined  with 
the  potash,  which  is  contained  in  these  roots  in  the  pro- 
portion of  Y^^  of  its  weight,  would  produce  salt-petre. 

If  we  observe  a  plant  during  the  various  stages  of  its 
vegetation,  we  shall  perceive  at  these  different  periods  very 
remarkable  differences  in  the  odor,  taste,  consistency, 
&c. ;  from  this  circumstance  we  must  suppose  that  it  forms 
new-  products,  new  combinations,  and  consequently  new 
salts. 

Th^  alkaline  salts  are  the  most  abundant  in  green  her- 
baceous plants.  M.  de  Saussure  has  observed,  that  the 
ashes  of  young  plants  that  grew  upon  a  poor  soil  contained 
at  least  f  of  their  weight  of  alkaline  salts,  and  that  those 
of  leaves  of  trees  which  grew  from  their  buds  contained 
at  least  ^. 

The  proportion  of  alkaline  salts  diminishes  in  propor- 
tion as  the  plants  advance  in  age :  this  remark  applies 
equally  to  annual  plants  and  to  the  leaves  of  those  trees 
that  shed  their  foliage  in  autumn.  The  ashes  of  seeds 
contain  a  greater  proportion  of  alkaline  salts,  than  those 
of  the  plants  that  produced  them. 

These  facts  are  very  important  to  those  who  are  engaged 
in  the  manufacture  of  salts  furnished  by  the  combustion 
of  vegetable  substances;  since  they  show  clearly  that  it 
cannot  be  equally  advantageous  to  them  to  consume  all 
sorts  of  plants,  nor  at  all  periods  of  their  growth. 

Next  to  the  alkaline  salts,  the  earthy  phosphates  of  lime 
and  magnesia  are  the  most  abundant  in  plants,  and,  like 
the  first,  these  diminish  in  quantity  in  proportion  to  the  age 
of  the  plant.  Plants  also  contain,  but  in  very  small  pro- 
portions, silica,  and  some  metallic  oxides,  especially  those 
of  iron. 


ARTICLE   VL 

The  Changes  produced  in  Plants  by  Nourishment^  resumed. 

Plants  are  principally  nourished  through  their  leaves 
and  roots  :  the  first  absorb  from  the  atmosphere  oxygen, 
carbonic  acid,  and  water;   and  the   second  receive  from 


100  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

the  soil  the  oxygen  and  carbonic  acid  contained  in  it  in  a 
free  state,  or  dissolved  in  water,  and  also  the  juices  and 
salts  which  are  mixed  with  the  earth. 

Water  appears  to  be  the  necessary  vehicle  of  nearly  all 
the  nutritive  portions  of  the  soil ;  so  that  it  not  only  serves 
to  nourish  plants,  by  yielding  to  them  the  elements  of 
which  it  is  itself  composed,  but  it  conveys  into  their  inter- 
nal organs  all  the  substances  which  can  serve  them  as 
food. 

The  substances  which  chiefly  afford  nourishment  to 
plants,  present  in  their  composition  only  carbon,  hydrogen, 
and  oxygen  ;  the  numerous  products  formed  in  the  course 
of  vegetation,  do  not  upon  analysis  furnish  any  other  prin- 
ciples ;  the  salts,  the  earths,  and  the  metals  are  generally 
found  in  them  in  very  small  quantities,  and  under  a  very 
different  form  from  that  in  which  they  exist  in  the  soil. 

Strictly  speaking,  the  three  principles  necessary  to  vege- 
tation are  oxygen,  carbon,  and  hydrogen,  combined  in  va- 
rious proportions ;  and  it  is  this  difference  in  the  propor- 
tions which  causes  the  immense  variety  in  the  vegetable 
kingdom :  some  hundredths  more  or  less  of  carbon,  oxy- 
gen, or  hydrogen  change  the  character  of  the  body. 

The  chymist  in  experimenting  upon  dead  plants  pro- 
duces at  pleasure  a  part  of  these  effects  :  fermentation  and 
spontaneous  decompositions  give  rise  to  a  great  number. 
But  the  constant  uniformity  of  the  products  in  the  same 
species  of  plants,  and  the  analogy  existing  between  those 
derived  from  different  species  of  the  same  genus;  their 
variety  in  the  different  organs,  and  the  peculiar  com- 
pounds, apparently  so  complicated,  of  each  one  of  them, 
form  altogether  so  many  phenomena  beyond  the  power  of 
art  to  explain. 

We  know  the  substances  received  by  plants,  and  those 
which  they  reject;  we  determine  by  analysis  the  nature 
and  the  composition  of  the  products  which  they  form ;  but 
this  is  the  utmost  extent  of  our  knowledge.  All  that  passes 
within  the  plant  is  still  a  mystery,  and  belongs  to  the  laws 
of  vitality,  which  modify  by  their  action  those  physical 
laws  that  are  known  to  us. 

However,  as  the  laws  of  vitality  governing  vegetables 
are  in  their  application  less  independent  of  the  physical 
laws,  than  those  that  reign  in  the  animal  kingdom,  we  can 
even  now  raise  a  portion  of  the  veil,  and  follow  at  least 
the  progress  of  the  changes,  though  we  can  as  yet  neither 
produce  them  nor  discover  their  mode  of  action. 


CHANGES    PRODUbEB    BY    N0tJRX3HM£NT.  Idi 

The  germination  of  seeds  and  tiipj  fjivt^lJiqgipf  \^t(^',ifL'> 
the  spring,  are  almost  entirely  the  results  of  physical  laws : 
oxygen  is  the  only  agent  necessary  to  produce  them  :  wa- 
ter and  heat  are  necessary  auxiliaries,  but  they  do  not  in 
any  way  enter  into  the  new  combinations ;  they  only  facili- 
tate the  changes  that  are  going  on.  The  oxygen  unites 
with  carbon  to  form  carbonic  acid  gas ;  by  this  means  the 
mucilage  and  starch ,  are  reduced  to  the  state  of  a  milky 
liquor,  which  serves  as  the  first  aliment  of  the  young  plant 
or  twig. 

As  soon  as  the  plant  has  unfolded  its  leaves,  or  tlie  radi- 
cles of  the  seed  have  penetrated  into  the  soil,  the  system 
of  nourishment  is  changed  :  every  part  of  the  plant  in  con- 
tact with  the  atmosphere  gives  out  carbon  during  the 
night,  or  when  in  darkness ;  but  the  carbonic  acid  which 
this  forms  with  oxygen,  instead  of  remaining  in  the  air,  as 
at  the  period  of  germination,  is  absorbed  principally  by 
the  roots  and  leaves,  and  decomposed  in  the  last  by  the 
solar  rays;  the  carbon  remaining  fixed  in  the  plant,  whilst 
the  oxygen  is  exhaled  in  the  form  of  a  gas.  Plants  are 
likewise  nourished  by  that  aqueous  fluid  which,  constantly 
existing  in  the  atmosphere  in  greater  or  less  abundance,  is, 
by  the  diminished  temperature  of  the  air  during  the  night, 
deposited  in  the  form  of  dew.  The  water  contained  in 
the  soil  dissolves  the  juices  of  the  manures,  and  transmits 
them  to  the  plants. 

But  in  order  that  plants  should  flourish,  it  is  not  sufli- 
cient  that  they  have  at  their  disposition  all  their  necessary 
aliments ;  it  is  further  requisite,  that  the  elaboration  of 
these  be  favored  by  other  causes  possessing  equal  influ- 
ence over  vegetation. 

I  have  already  remarked,  that  leaves  do  not  transpire 
oxygen  excepting  when  exposed  to  the  rays  of  the  sun ;  so 
that  the  carbonic  acid  remains  in  the  plant  during  the 
whole  time  that  the  solar  rays  are  hidden.  The  establisli- 
ment  of  this  fact  enables  us  to  explain  many  of  the  most 
important  phenomena  of  vegetation  :  we  learn  from  it,  why 
plants  that  grow  in  the  shade  never  produce  fruits  having 
the  same  taste,  perfume,  or  texture  as  those  borne  by 
plants  of  the  same  kind  growing  in  the  sun  ;  and  why  the 
various  sorts  of  fodder  and  green  herbs  are  of  bad  quality, 
when  the  sun  has  not  access  to  them  to  facilitate  the 
decomposition  of  carbonic  acid  and  the  elaboration  of  the 
nutritive  fluids. 
9* 


102  CMYMiSTSlY    APPLIED    TO    AGRICULTURE. 

.  Ind'apendeatly  of  tlie  light  of  the  sun,  without  which 
plants  cannot  flourish,  vegetation  requires  a  certain  degree 
of  heat;  buds  generally  do  not  begin  to  unfold  till  the  at- 
mosphere is  at  the  temperature  of  from  50°  to  54° :  and 
vegetation  gains  strength  in  proportion  as  the  heat  of  the 
atmosphere  increases,  provided  that  at  the  same  time  the 
earth  be  sufficiently  moist  for  the  water  to  convey  to  the 
plants  the  nourishment  it  contains,  and  to  furnish  to  them 
the  means  of  transpiration.  The  influence  of  temperature 
over  vegetation  is  so  marked,  that  we  can  see  the  latter  di- 
minish as  the  heat  lessens,  and  resume  its  energies  as  that 
is  augmented.  Warmth  renders  the  sap  fluid,  and  quick- 
ens its  circulation ;  cold  thickens  it  and  renders  it  stag- 
nant. If  a  right  degree  of  atmospheric  temperature,  the 
influence  of  the  solar  rays,  or  a  suitable  quantity  of  the 
aqueous  fluid  be  wanting,  the  growtji  of  plants  is  retarded. 
Thus  we  see  it  is  not  enough  that  plants  are  abundantly 
supplied  with  nourishment ;  it  is  necessary  that  the  con- 
coction of  it  should  be  favored  by  agents  which  concur  in 
causing  its  digestion. 

When  the  soil  is  too  abundantly  provided  with  manures, 
especiafly  of  kinds  that  may  be  easily  conveyed  into  plants 
by  water,  their  growth  may  be  prodigiously  increased  ;  but 
if  the  digestive  organs  and  the  constant  influence  of  the 
sun  do  not  concur  in  elaborating  their  juices,  the  result 
will  be,  as  I  have  before  remarked,  a  kind  of  obesity  ;  and 
none  of  the  products  will  have  either  the  savor  or  the  odor 
that  they  would  have  acquired  if  the  nourishment  had  been 
less  abundant  and  better  digested.  It  is  not  uncommon 
for  fruits  and  herbs  to  yield  the  odor  peculiar  to  the  ma- 
nure with  which  they  have  been  nourished,  when  it  has 
been  too  abundantly  supplied. 

The  juices  circulate  in  plants,  not  only  with  the  same 
regularity  of  movement  that  we  observe  in  animals  more 
perfectly  organized,  but  with  a  degree  of  force  sufficient  to 
carry  them  into  all  the  organs,  that  they  may  receive  in 
each  one  of  them  a  peculiar  elaboration. 

The  roots  absorb  fluids  from  the  earth  by  means  of  their 
capillary  vessels  ;  but  the  force  with  which  they  are  con- 
veyed into  the  internal  organs  of  the  plant,  and  even  into 
the  leaves,  where  their  carbon  combines  with  oxygen,  is 
superior  to  that  of  capillary  attraction,  and  the  weight  of 
the  atmosphere. 

The  celebrated  Hales  cut  a  branch  of  a  vine  four  or  five 


CHANGES   PRODUCED    BY    NOURISHMENT.  103 

i 

years  old  ;  this  he  cemented  carefully  into  a  glass  tube  bent 
in  the  form  of  a  siphon,  filled  with  mercury  ;  by  the  force 
of  the  ascending  sap  alone,  the  mercury  rose  at  the  end  of 
some  days  to  38  inches.  M.  Mirbel  has  confirmed  this  ex- 
periment, and  added  many  others  of  great  importance,  but 
which  would  carry  me  too  far  from  my  subject. 

As  the  sap  circulates  in  plants  by  the  aid  of  numerous 
vessels  and  cells,  which  have  no  rectilinear  communica- 
tion, the  force  with  which  the  sap  ascends  may  be  ex- 
plained by  a  principle  deduced  from  the  experiments  of 
M.  de  Montgolfier,  who  has  proved,  that,  by  means  of  a 
very  small  force,  liquids  may  be  raised  to  an  almost  in- 
definite height,  provided  the  pressure  of  the  column  of 
liquid  be  destroyed  by  numerous  interceptions  or  valves. 

The  force  with  which  the  sap  ascends  is  proportioned 
to  the  health  of  the  plants,  and  the  abundance  of  its 
transpiration  :  a  stalk  deprived  of  its  leaves  will  raise 
less  mercury  than  one  retaining  them ;  and  trees  having 
smooth,  spongy  leaves  abounding  in  exhaling  pores,  such 
as  the  wild  quince,  the  alder,  the  sycamore,  the  peach, 
the  cherry,  die,  raise  it  to  a  much  greater  height  than 
those  of  which  the  leaves  are  varnished  or  dry.  The 
beautiful  experiments  of  Hales  have  verified  these  results. 

All  the  water  imbibed  by  the  different  parts  of  plants, 
but  especially  by  the  roots,  is  first  employed  in  mixing 
the  juices,  and  facilitating  their  circulation  ;  it  is  then 
decomposed,  and  a  part  of  it  furnishes  hydrogen,  so  abun- 
dant in  the  products  of  vegetation,  but  the  greatest  por- 
tion is  evaporated,  principally  by  the  leaves,  and  thus 
maintains  their  temperature  below  that  of  the  atmosphere 
during  the  burning  heat  of  summer.  Hales  observed, 
that  a  sun-flower  plant  transpired  by  the  leaves,  in  the 
space  of  twelve  hours,  1  lb.  14  oz.  of  water. 

The  cold  which  begins  to  make  itself  felt  in  autumn, 
retards  the  movement  of  the  sap ;  the  fluids  become 
thickened,  the  solids  contracted,  the  leaves  cease  to  in- 
hale, and  the  roots  no  longer  absorb  nourishment  from 
the  soil,  and  at  length  the  vital  functions  are  suspended. 
The  returning  warmth  of  spring  brings  renewed  life  to 
the  organs ;  the  fluids  and  the  solids  receive  a  greater 
expansion,  circulation  is  restored,  and  the  sap  deposited 
in  the  vessels  during  the  summer  and  earlier  part  of  au- 
tumn, affords  the  first  nourishment  to  plants. 

The  branches  of  trees  that  are  lopped  off  in  winter,  put 


104  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

forth  buds  and  stalks  in  the  spring ;  a  branch  of  a  vine 
introduced  during  the  winter  into  a  hot-house,  vegetated 
as  it  would  have  done  in  the  spring,  whilst  that  portion  of 
it  which  remained  exposed  to  the  cold  experienced  no 
change.  Plants  that  have  been  browsed  in  autumn,  do 
not  put  forth  so  early,  nor  with  so  much  strength  as  those 
of  which  the  roots,  and  the  parts  immediately  surmounting 
them,  have  been  preserved  by  mowing. 

All  agriculturists  have  observed,  that  young  trees  trans- 
planted in  the  spring  appear  to  flourish  for  three  or  four 
months,  and  then  die;  if  when  taken  up  they  have  ex- 
amined their  roots,  they  have  almost  invariably  found 
that  they  presented  no  appearance  of  having  increased ; 
which  proves  that  vegetation  is  carried  on  in  the  spring 
by  the  nourishment  provided,  and  deposited  in  plants  be- 
fore the  fall  of  the  leaves. 

The  difference  which  exists  in  the  vegetation  of  the 
same  branch,  one  end  of  which  is  placed  in  the  earth, 
and  the  other  rising  above  it,  must  strike  every  observer. 
The  part  which  is  planted  in  the  soil,  sends  forth  roots, 
whilst  that  which  rises  into  the  air  produces  leaves ;  and 
if  any  part  of  the  root  be  uncovered,  so  as  to  come  in 
contact  with  the  air,  it  produces  stalks  and  leaves ;  whilst 
that  which  remains  beneath  the  soil  continues  to  grow  as 
the  root  of  them.  All  parts  of  plants  then  are  organ- 
ized by  their  growth  in  such  a  manner,  as  shall  enable 
them,  most  conveniently,  to  imbibe  at  the  same  time  their 
nourishment  from  the  soil  and  from  the  atmosphere. 

It  is  in  the  power  of  art  to  influence  the  flow  of  the 
sap,  nearly  at  will.  When  the  nourishment  afforded  by 
the  earth  is  too  abundant,  it  is  but  imperfectly  digested, 
and  is  exclusively  employed  in  the  growth  of  the  plants; 
a  tree  in  this  case  produces  neither  flowers  nor  fruit,  but 
expends  all  its  strength  in  leaves  and  wood.  To  remedy 
this  superabundance  of  sap,  some  of  the  roots  may  be 
separated ;  or  what  is  still  better,  incisions  may  be  made 
in  the  bark  of  the  tree  to  cause  the  escape  of  a  portion  of 
the  sap. 

If  it  be  wished  to  facilitate  the  growth  of  the  fruit,  a 
portion  of  the  branches  may  be  pruned,  and  part  of  the 
fruit  be  plucked  off;  in  this  way  a  greater  quantity  of 
sap  may  be  supplied  to  the  fruit  that  remains ;  tight 
ligatures  upon  the  branches,  and  incisions  surrounding 
them   through  the  whole  thickness  of  the  bark,  produce 


CHANGES    PRODUCED    BY    NOURISHMENT.  105 

the  same  eflfect.  The  pruning  of  fruit  trees  is  principally 
designed  to  limit  the  production  of  fruit  to  the  quantity 
that  can  be  properly  nourished  by  the  plant.  The  graft- 
ing which  is  practised  upon  trees  of  analogous  species, 
only  presents  to  the  juices  of  the  wild  tree  an  organic 
tissue  different  from  its  own  ;  in  the  cells  of  which  the 
juices  receive  a  peculiar  elaboration,  which  changes  the 
nature  of  their  products. 

It  is  not  by  an  analysis  of  plants,  nor  by  the  proportion 
of  their  constituent  principles,  which  can  be  extracted  by 
water,  that  we  can  judge  of  the  nutritive  quality  of  vege- 
tables, or  other  alimentary  substances.  I  have  already 
proved,  that  a  nutritive  substance,  deprived  of  all  its  solu- 
ble parts  by  water,  is  capable,  in  the  progress  of  its  de- 
composition, of  forming  new  and  soluble  compounds.  It 
is  only  by  experiments,  and  by  the  effects  of  this  or  that 
kind  of  food  upon  animals,  that  we  can  ascertain  the 
differences  existing  between  various  nutritive  bodies. 

The  digestive  juices  of  the  stomachs  of  animals  and 
the  organs  of  plants  animated  by  vital  powers,  of  which 
we  are  ignorant,  have  also  their  chymistry,  with  which 
we  are  unacquainted,  and  of  which  we  can  understand 
only  the  results.  It  is  surely  erroneous  to  pretend  to 
determine  the  quantity  of  nourishment,  by  that  portion 
/  which  can  be  extracted  from  any  article  of  food  by  water  ; 
but  upon  this  principle  Davy  has  represented  the  nutritive 
virtue  of  beets  by  the  number  of  136,  and  that  of  carrots 
by  98  ;  whilst  M.  Thayer  has  by  his  experiments  estimated 
that  of  the  first  to  be  57,  and  of  the  last  98.  Upon  the 
same  principle  Davy  has  valued  the  effects  of  linseed 
cakes  at  151,  compared  with  those  of  beets  as  136  ; 
while  it  has  been  proved  that  70  lb.  of  beets  are  hardly 
equivalent  in  nourishment  to  10  lb.  of  linseed  cakes. 

In  order  to  estimate  the  nutritive  merits  of  any  sub- 
stance, it  is  necessary  to  have  less  regard  to  its  chymical 
character,  than  to  the  nature  of  the  animal  to  be  nourished 
by  it  :  one  is  disgusted  by  that  which  pleases  another  ; 
and  this  will  decompose  what  that  will  reject ;  it  is  only 
by  observation  that  we  can  decide. 

These  principles  are  still  less  applicable  to  the  nourish- 
ment of  plants,  than  of  animals  ;  because  of  the  first  it 
is  necessary  that  their  food  should  be  presented  to  them, 
and  in  a  state  of  solution  or  mixture ;  whilst  the  last  seek 
theirs  where  it  maybe  found,  and  make  choice  of  such 


106  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

as  is  suitable  for  them;  but  in  both  cases  the  nutritive 
virtues  of  the  food  can  be  estimated  only  by  the  results 
of  its  elaboration  in  the  digestive  organs,  and  by  the 
effects  produced  on  the  economy  of  the  animal  or  vegeta- 
ble. It  should  besides  be  remembered,  that  the  nutritive 
qualities  of  the  various  products  of  vegetation  depend 
less  upon  their  weight,  than  their  kind ;  and  that  a  sub- 
stance may  be  insoluble  in  water,  which  may,  when  acted 
upon  by  the  gastric  juices,  become  excellent  food. 


CHAPTER  VI. 

IMPROVEMENT    OF    THE    SOIL. 


To  improve  the  soil  is  to  render  it  more  suited  to  vege- 
tation by  ameliorating  the  nature  of  the  earth.  All  then 
which  tends  to  dispose  a  soil  favorably  towards  plants,  in 
connection  with  the  action  which  is  exercised  upon  them 
by  air,  water,  temperature,  manures,  «fec.,  may  be  justly 
termed  improvement.  Thus,  before  undertaking  to  im- 
prove a  soil,  it  is  necessary  to  be  acquainted  with  its 
qualities,  and  particularly  with  its  defects,  that  we  may 
apply  to  it  the  means  of  improvement  it  requires. 

This  preliminary  knowledge  of  the  defects  of  a  soil 
implies  a  second,  which  is  that  of  all  the  agents  which 
can  be  employed  in  its  improvement :  the  correction  of 
known  feults  can  only  be  performed  by  means  of  sub- 
stances possessing  opposite  qualities. 

As  in  the  term  improvement  is  implied  all  which  can 
tend  to  ameliorate  a  soil,  it  necessarily  has  a  very  exten- 
sive signification ;  it  comprehends  operations  purely  me- 
chanical, and  the  use  of  those  earthy  and  nutritive  mix- 
tures, which  are  produced  by  art;  it  likewise  comprises 
all  the  means  which  can  be  employed  to  direct  advanta- 
geously the  action  of  air,  water,  heat,  &.c.  It  is  in  all 
these  relations,  that  it  is  necessary  to  consider  the  great  art 
of  improvement. 

The  best  earths  produce  but  little,  if  they  be  not  stirred 
by  the  spade,  the  hoe,  or  the  plough.  This  operation 
divides  and  softens  the  earth,  brings  to  the  surface  the 
manures  of  all  kinds,  which  the  rains  had  caused  to  sink 


IMPROVEMENT    OF    THE    SOIL.  107 

below  it ;  facilitates  the  spreading  of  the  roots,  mixes  the 
dung  with  the  earth,  and  renders  its  action  more  equal ;  it 
destroys  weeds,  and  causes  them  to  serve  as  manure ;  and  it 
frees  the  soil  from  vermin,  which  would  otherwise  multiply 
in  it  to  the  destruction  of  the  harvests. 

This  operation  is  performed  upon  all  soils  of  what  kind 
soever;  it  forms  the  very  basis  of  agriculture;  without  it 
there  can  be  no  harvest.  The  tillage  by  the  hoe  is  much 
more  perfect  than  that  by  the  plough,  but  the  spade  is  a  still 
more  efficacious  implement.  The  plough  divides  and  turns 
the  soil  with  less  'exactness  than  either  of  the  others ;  and 
notwithstanding  the  crossed  and  multiplied  furrows,  there 
will  be  some  portions  of  the  intervals  and  intersections, 
where  the  soil  will  remain  untouched  ;  but  as  tillage  by  the 
plough  is  the  least  costly,  and  the  most  expeditious,  it  has 
generally  received  the  preference. 

I  know  a  little  village  in  Touraine,  between  the  Cher  and 
the  Loire,  where  all  the  lands  are  cultivated  by  the  spade, 
and  their  produce  is  always  double  that  of  any  in  the 
neighbourhood ;  the  inhabitants  have  become  rich,  and  the 
soil  has  doubled  in  value.  In  Bremont,  between  Loches 
and  Chinon,  they  employ  no  other  means  of  cultivating  a 
very  fertile  soil ;  but  this  method  can  be  used  only  on  small 
estates,  or  in  a  country  where  labor  is  very  abundant  and  to 
be  procured  at  a  low  price  :  I  do  not  doubt,  however,  that 
there  are  some  localities  where  it  could  be  conducted  with 
profit,  if  it  should  be  employed  from  time  to  time  to 
ameliorate  successive  portions  of  land,  especially  those 
that  have  been  used  for  the  cultivation  of  such  plants  as 
have  long  roots. 

In  the  alluvial  soils  formed  by  the  deposits  of  the  Loire, 
between  Tours  and  Blois,  the  farmer  reaps  fi-om  his  land  a 
harvest  of  corn,  and  afterwards  lets  it  to  persons,  who  turn 
it  to  the  depth  of  a  foot,  with  spades,  and  raise  upon  it  legu- 
minous plants. 

From  the  effects  produced  by  this  kind  of  tillage,  we  may 
perceive,  that  it  cannot  be  employed  equally  in  all  soils,  or 
indifferently  at  all  seasons,  nor  be  always  carried  to  the 
same  depth.  A  light,  porous,  calcareous,  or  sandy  soil 
requires  less  tilling  than  that  which  is  compact  and  argilla- 
ceous ;  and  this  last  requires  to  be  stirred  more  deeply 
than  the  first,  because  otherwise  the  roots  cannot  penetrate 
it  and  fasten  themselves  in  it ;  neither  can  the  air  gain 
access  to  deposit  upon  them  its  kindly  moisture. 


108  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Calcareous,  sandy,  and  siliceous  soils  may  be  tilled  at 
any  time,  whilst  the  argillaceous  soils  are  in  a  fit  state  for  the 
plough  only  at  certain  seasons,  which  must  be  eagerly 
seized  upon  by  the  farmer  ;  the  action  of  the  plough  upon 
these  lands  immediately  after  rain,  only  leaves  marks  in 
the  mud  ;  and  if  they  be  allowed  to  remain  till  they  are 
thoroughly  dry,  they  become  impenetrable  by  it ;  the  in- 
terval between  these  two  periods  is  the  time  most  favorable 
for  tilling. 

The  best  tilling  does  not  always  prepare  soils  entirely  for 
cultivation ;  some  are  not  sufficiently  divided  or  crumbled  ; 
others  are  not  sufficiently  levelled,  and  it  is  only  by  the  as- 
sistance of  the  harrow,  or  the  roller,  that  the  labor  of  tillage 
can  be  completed.  By  dragging  the  harrow  in  all  direc- 
tions over  a  newly  ploughed  field,  the  clods  left  by  the 
plough  are  turned  over,  the  uprooted  weeds  are  carried  off, 
and  a  more  equal  division  is  given  to  all  parts  of  the  soil. 
The  strength  and  weight  of  the  harrow  must  be  in  propor- 
tion to  the  resistance  offered  by  the  nature  of  the  soil.  The 
harrow  can  be  employed  advantageously  in  opening  the  soil 
of  artificial  meadows,  especially  those  of  clover,  when  the 
surface  has  become  a  crust  impenetrable  by  air  or  water ; 
the  operation  of  harrowing,  in  this  case,  should  be  performed 
early  in  the  spring  of  every  other  year,  or  immediately  after 
having  cut  the  first  crop  of  fodder;  by  this  means,  many 
plants  injurious  to  the  soil  are  destroyed,  and  meadows  are 
restored,  which  would  have  been  constantly  deteriorating. 
I  have  practised  harrowing  fields  of  grain,  early  in  the 
spring,  with  great  success,  and  have  found  the  harvests 
from  them  uniformly  much  finer,  than  from  those  that  had 
not  been  harrowed ;  but  it  was  necessary  to  pay  attention 
to  having  the  harrows  very  light,  and  made  with  wooden 
teeth. 

The  roller  I  have  found  to  produce  an  excellent  effect 
afi;er  the  seed  was  covered  ;  it  unites  and  levels  the  surface 
of  the  ground,  and  is  particularly  useful  for  porous  and  light 
soils,  and  for  those  earths  of  which  the  constituent  particles 
are  fine  and  light.  If  such  soils  have  not  received  a  suitable 
degree  of  firmness  from  the  roller,  high  winds  and  rains 
are  apt  to  carry  off"  the  upper  layer,  and  to  leave  bare  the 
roots  of  the  plants.  Another  advantage  arising  from  the 
application  of  the  roller  is,  that  the  soil  which  has  been 
subjected  to  it,  presents  fewer  obstacles  to  the  use  of  the 
scythe,  or  of  the  sickle. 


IMPROVEMENT    OF    THE    SOIL.  109 

When  frosts  have  bound  up  the  soil^  and  it  has  been 
again  set  free  by  thaws,  the  roots  are  left  almost  without 
support,  as  the  earth  scarcely  adheres  to  them  :  the  roller, 
applied  to  lands  as  soon  as  they  are  firm  enough  to  admit 
of  its  being  passed  over  them,  is  very  useful,  as  it  reunites 
the  earth  to  the  roots,  and  repairs  the  injury  done  by  the 
frosts  and  thaws. 

A  judgment  of  the  mixture  necessary  for  amending  a 
soil,  can  be  formed  only  from  a  perfect  knowledge  of  its 
defects. 

A  soil  in  the  composition  of  which  the  best  earths  are 
united,  does  not  need  to  be  improved  by  the  addition  of 
new  earthy  principles  :  good  tillage  and  the  application  of 
manure  are  sufficient  to  render  it  fertile  :  but  that  soil  in 
which  any  one  of  the  earths  predominates  to  such  a  degree, 
as  to  give  a  character  to  the  whole  mass,  requires  to  be 
corrected  by  the  admixture  of  substances  possessing  oppo- 
site qualities.  I  shall  distinguish  soils  as  argillaceous, 
calcareous,  siliceous,  and  sandy :  these  divisions  seem  to 
comprise  all  those  requiring  to  be  amended  ;  and  the  quali- 
ty of  the  earth  predominating  in  each,  indicates  suflSciently 
the  kind  of  improvement  suitable  to  it. 

An  argillaceous  or  clayey  soil  is  rendered  pasty  by 
rains,  and  it  is  hardened  and  cracked  by  heat ;  it  absorbs 
moisture  from  the  air  only  on  its  surface,  but  it  imbibes 
abundantly  the  water  of  rains,  and  retains  it  by  so  strong 
an  affinity,  that  when  the  supply  is  in  excess,  it  remains 
till  it  stagnates  and  causes  the  roots  of  plants  to  decay. 

An  argillaceous  soil  is  unfavorable  to  cultivation ;  for 
when  it  is  acted  upon  by  the  frost,  the  water  contained  in 
*ts  interstices  expands  by  freezing,  and  the  thaw  which 
sets  the  earth  free,  divides  it  into  morsels  with  which  the 
roots  of  plants  have  so  little  cohesion,  that  they  may  be 
drawn  out  from  it  almost  without  resistance  :  the  roots  are 
at  such  times  in  the  state  of  newly  planted  vegetables ;  they 
have  need  of  being  established,  of  being  fixed  to,  and 
united  with  the  soil,  in  order  to  vegetate.  If  in  this  state  a 
root  be  attacked  by  a  new  frost,  it  dies  ;  for  not  being  pro- 
tected by  the  close  adhesion  of  the  soil,  the  cold  acts  upon 
it,  as  if  it  were  exposed  defenceless  upon  the  surface  :  it  is 
this  which  renders  alternate  frosts  and  thaws  more  injuri- 
ous to  fields  of  grain,  and  to  artificial  meadows,  than  th€ 
severest  cold  which  continues  till  spring.     It  is  to  obviate 


no  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

this  evil  resulting  from  a  second  freezing,  that  1  propose 
levelling  the  earth  by  the  roller,  after  the  first  thaw. 

These  defects,  more  marked  in  argillaceous  soils  than 
in  others,  require  to  be  amended ;  every  thing  which  will 
tend  to  soften  the  earth,  to  render  it  more  light  and  po- 
rous, and  to  facilitate  the  passage  of  water  through  it,  is 
perfectly  adapted  to  this  kind  of  soil  :  thus  the  mixture  of 
earths,  and  of  calcareous  sands,  broken  shells,  chalks,  and 
lean  marl ;  deep  and  frequent  ploughing  ;  the  turning  in  of 
green  crops ;  the  use  of  hot  manures,  such  as  the  dung, 
fresh  from  the  barn-yard,  of  sheep  and  horses,  that  of 
pigeons  and  fowls,  poudrette^  and  the  salts,  are  so  many 
means  which  may  be  made  to  concur  in  the  improvement 
of  argillaceous  soils. 

I  have  had  opportunities  of  seeing  many  soils  possessing 
the  same  faults  as  the  argillaceous,  but  not  owing  to  the 
excess  of  that  earth  ;  for  by  mixing  a  portion  of  the  soils 
in  water,  I  satisfied  myself  that  there  was  not  contained  in 
them  any  coarse  sand  ;  so  that  the  whole  was  formed  by  a 
union  of  particles  so  minutely  divided  as  to  present  no 
consistency  in  the  mass  ;  but  forming  a  paste  with  water, 
and  cracking  when  that  liquid  was  evaporated.  The  only 
difference  between  the  argillaceous  soils  and  these  is,  that 
the  latter  when  dried  do  not  possess  the  hardness  of  the 
former,  but  on  the  contrary  fall,  under  the  pressure  of  the 
hand,  into  a  nearly  impalpable  powder.  The  state  of  these 
soils  is  owing  to  their  having  been  exhausted  by  long  cul- 
tivation :  some  of  the  kind  which  I  have  owned,  I  have 
been  able  to  restore  to  fertility  by  applying  a  portion  of 
sandy  marl  containing  ^/^  of  calcareous  sand. 

Calcareous  soils  possess  properties  entirely  opposite  to 
those  of  the  argillaceous  soils;  the  rains  filtrate  easily 
through  them,  and  they  throw  off  moisture  readily  by  evap- 
oration ;  the  air  can  penetrate  them,  to  deposit  amongst 
their  particles  the  moisture  with  which  it  is  charged :  and 
this,  especially  in  hot  climates,  conduces  greatly  to  their 
fertility.  The  tillage  of  these  soils  is  always  easy  ;  and  as 
they  are  light  and  porous,  provided  they  have  sufficient 
depth,  roots  spread  in  them  easily.  Though,  from  their 
character,  these  soils  do  not  require  so  much  amendment 
as  those  that  are  argillaceous,  they  may  still  be  im- 
proved ;  especially  by  giving  to  them  the  power  of  retain^ 
ing  water  for  a  longer  time,  that  they  may  thus  be  better 
able  to  supply  the  wants  of  plants :  for  this  purpose,  it  is 


IMPROVEMENT    OF    THE    SOIL.  Ill 

sufficient  to  add  to  them  some  fat  marl,  or,  for  want  of 
that,  calcined  clay.  These  soils,  being  naturally  warm, 
require  the  fresh  dung  of  neat  cattle  ;  the  unctuous  ma- 
nures are  best  adapted  to  them. 

Sand  incorporated  with  finely  divided  calcareous  earth, 
forms  an  excellent  means  of  amendment,  especially  if  it 
be  combined  with  clay  or  fat  marl.  I  have  likewise  seen 
the  rich  mud  drawn  from  rivers,  used  with  great  success 
in  improving  calcareous  soils. 

There  is  a  great  resemblance  in  many  respects  between 
sandy  and  siliceous  soils :  both  are  formed,  generally,  by 
the  alluvion  of  rivers;  both  of  them  are  nearly  barren 
when  they  contain  no  other  principles ;  and  both  of  them 
form  the  base  of  very  good  soils,  if  they  are  suitably 
amended. 

When  these  soils  are  formed  by  the  inundations  of  rivers, 
or  by  streams  that  have  taken  new  channels,  they  are  for 
some  time  destitute  of  fertility  ;  but  the  successive  swell- 
ings of  the  rivers  deposit  a  rich  mud,  which  becomes  at 
length  incorporated  with  the  first  layer;  and  when  the 
whole  is  well-  united,  an  excellent  soil  is  formed.  This 
mud  is  very  fertilizing,  from  its  containing  the  remains  of 
all  those  animal  and  vegetable  substances,  which  muddy 
waters  carry  with  them  in  their  overflowings.  When  these 
soils  are  left  to  themselves,  we  see  plants  springing  up  on 
them  spontaneously,  from  the  seeds  deposited  by  the  waters 
•which  conveyed  them  there. 

Soils  of  this  kind  rarely  require  manuring :  successive 
inundations  constantly  renew  their  fertility  :  their  level  is 
raised  by  the  accumulation  of  deposits,  till  at  length  they 
are  not  subject  to  being  overflowed,  excepting  when  the 
rivers  rise  unusually  high  ;  and  in  those  cases  the  large 
pebbles,  which  never  float  upon  the  surface  of  water,  can- 
not be  deposited  upon  them.  These  lands,  so  valuable  for 
agriculture,  do  not  offer  much  resistance  to  the  rapid 
current  of  great  inundations,  which  often  carry  them  off*; 
nor  to  the  masses  of  ice,  which  at  the  breaking  up  of  the 
iVosts  gully  and  furrow  them.  I  believe  I  ought  here  to 
devote  a  few  lines  to  pointing  out  some  methods  for  pre- 
serving these  valuable  lands  from  such  accidents  :  it  is  of 
more  consequence  to  preserve  property  than  to  improve  it. 

In  order  to  prevent  the  evils  of  which  I  have  just  spoken, 
it  is  customary  to  surround  lands  of  this  kind  with  planta- 
tions of  trees ;    but  trees  of  a  large  size  cannot  take  root 


113  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

firmly  in  a  sandy  and  easily  disturbed  soil.  The  winds 
are  generally  very  violent  in  those  valleys  through  which 
large  rivers  flow ;  and  these,  by  the  violent  motion  which 
they  give  to  the  branches,  twisting  them  in  every  direc- 
tion, loosen  the  roots  ;  and  the  earth  being  continually  dis- 
turbed, the  water  penetrates  in,  and  softens  it,  so  that  when 
an  overflow  of  the  river  happens,  the  breaches  thus  made  in 
the  soil  lessen  its  powers  of  resistance  to  the  flood. 

If  we  observe  carefully  the  action  of  currents  upon  tlie 
great  trees  surrounding  lands  situated  upon  the  banks  of  a 
stream  or  river,  or  upon  an  island  lying  in  the  course  of 
one,  we  shall  be  convinced,  that,  so  far  from  preserving,  they 
facilitate  the  destruction  of  property ;  for  as  the  trunks  op- 
pose an  invincible  resistance  to  the  force  of  the  current,  it  is 
divided,  and,  encircling  them,  it  meets  again,  having  formec* 
a  complete  trench  in  the  soil.  Thus,  though  large  trees 
may  be  useful  for  turning  aside  masses  of  ice,  and  prevent- 
ing the  land  from  being  much  injured  by  them;  yet  in- 
stead of  preserving  it  from  the  ravages  of  a  rapid  current, 
they  become  powerful  auxiliaries  to  its  destructive  action. 

Flexible  shrubs  are  undoubtedly  preferable  to  large  trees ; 
their  roots  bind  the  soil ;  their  branches  lie  upon  the  sur- 
face of  the  earth,  and  preserve  it  from  injury  during  floods  ; 
but  these  shrubs  do  not  present  any  resistance  to  the  ice 
when  the  rivers  are  breaking  up ;  they  cannot  turn  aside 
the  masses  of  it,  and  force  them  to  remain  in  the  bed  of 
the  river,  that  they  may  not  furrow  the  meadow  or  field. 
It  is  necessary  then  to  unite  the  resistance  offered  by  trees 
^  with  that  of  flexible  shrubs  :  in  order  to  do  this,  it  is  neces- 
sary to  plant  willows  or  poplars  on  the  extremity  of  the 
banks,  at  the  distance  of  seven  or  eight  feet  apart ;  the 
heads  of  these  may  be  cut  off"  some  feet  above  the  height 
to  which  the  highest  floods  ever  reach  ;  the  water  willows 
or  osiers  may  be  planted  all  along  upon  the  shelf  or  slope 
of  the  land,  and  from  twenty-five  to  thirty  feet  inward.  In 
a  few  years  there  will  be  nothing  to  fear  from  floods  or  ice 
upon  land  defended  in  this  way ;  and  a  considerable  reve- 
nue will  arise  from  the  pruning  of  the  trees,  and  the  clip- 
pings of  the  osiers. 

After  having  placed  the  land  out  of  danger  from  inunda- 
tions, the  neighbourhood  of  a  river  opens  sources  of  profit 
that  are  very  simple,  and  may  be  taken  advantage  of  at  a 
slight  expense.  I  have  heretofore  remarked,  that  the  mud 
of  rivers  is  of  great  use  as  an  amender  of  soils,  and  that 


lMPROVEMEx\T    OF    THE    SOIL.  113 

when  employed  upon  alluvial  lands  it  supersedes  the  ne- 
cessity of  applying  to  them  other  manures ;  it  is  then  ad- 
visable, in  overflowings,  to  retain  that  mud,  and  that  only, 
which  possesses  the  greatest  power  of  fertilization. 

When  the  overflow  of  a  stream  commences  by  inun- 
dating that  portion  of  land  which  lies  highest  up  the  cur- 
rent, it  spreads  with  great  rapidity  over  the  whole  extent 
of  it,  furrowing  its  surface,  and  carrying  beyond  it  all  the 
most  finely  divided  mud  with  which  it  is  loaded ;  often  up- 
rooting crops  and  washing  away  the  manures  which  have 
been  deposited  during  former  overflowings ;  and  thus  im- 
poverishing instead  of  enriching  the  soil.  But  when  the 
rise  of  water  begins  down  the  current,  and  the  whole  tract 
of  land  is  slowly  submerged,  till,  even  to  the  head,  it  is 
under  water,  the  soil  receives  and  retains  all  the  richest 
and  most  finely  divided  mud,  as  well  as  the  remains  of 
animal  and  vegetable  substances  which  the  stream  has  in 
its  downward  course  washed  off*  from  other  tracts  of  coun- 
try, without  any  injury  being  sustained  either  by  the  har- 
vest or  the  land.  In  order  to  give  the  desired  direction  to 
the  current,  it  is  only  necessary  to  raise  the  head  of  the 
land,  or  that  part  which  lies  up  the  stream,  tmd  to  plant 
the  bank  with  osiers. 

By  these  means,  I  have  improved  and  tripled  the  value 
of  certain  islands  belonging  to  me  in  the  river  Loire.  These 
islands,  which  formerly  produced  but  little,  and  were  con- 
stantly receiving  injury  from  the  swellings  of  the  river,  are 
now  the  most  productive  portions  of  my  estate,  for  the  cul- 
tivation of  grains  and  beet  roots. 

When  sandy  or  siliceous  soils  are  situated  at  a  distance 
fi*om  a  river,  or  are  by  the  height  of  the  banks  placed 
beyond  the  reach  of  an  overflow,  it  is  necessary  to  amelio- 
rate them  by  art^  and  this  must  be  done  by  the  addition  of 
fat  marl,  clay,  dung,  &/C.  The  amendments  must  be  varied 
according  to  the  nature  and  fineness  of  the  sand  :  calcare- 
ous sands  retain  moisture  better  than  siliceous  sands. 

I  have  seen  some  soils  formed  of  beds  of  large  pebbles, 
which,  without  the  appearance  of  mould  upon  the  surface, 
produced  very  good  crops:  the  layer  of  pebbles,  which  was 
second  from  the  surface,  contained  earth  enough  to  enable 
the  plants  to  take  root  and  flourish. 

Soils  of  this  kind  furnish  excellent  pasture  for  sheep,  as 
may  be  observed  on  the  ancient  and  immense  alluvions  of 
the  Durance  and  the  Rhone.  The  herbage  upon  these  ii 
10* 


114  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

excellent,  and  suffers  less  from  drought  than  elsewhere; 
being  protected  from  the  ill  effects  of  the  scorching  rays  of 
the  sun,  by  the  pebbles  lying  above  its  roots.    • 

Rozier  made  the  experiment  of  covering  a  part  of  the 
soil  of  his  vineyards  with  pebbles,  and  found  it  attended 
with  good  effects,  especially  as  it  regarded  the  quantity  of 
wine  obtained.  One  of  my  friends  owned  in  Paris,  near 
the  barrier  d'Enfer,  an  enclosure,  of  which  the  soil  was  so 
dry  and  poor,  that  notwithstanding  all  the  pains  he  be- 
stowed upon  it,  he  could  never  make  any  fruit  trees  thrive 
there  :  in  order  to  amend  the  soil,  he  covered  it  with  a 
layer  of  good  earth,  which  he  mixed  with  the  dry  sand  of 
the  spot ;  this  gave  it  some  degree  of  fertility  ;  but  the  heat 
dried  his  plantations  so  much,  that  he  could  only  preserve 
them  by  frequent  and  very  expensive  waterings  :  he  at 
length  concluded  to  cover  the  surface  of  the  ground  with  a 
layer  of  pebbles,  and  from  that  time  the  trees  prospered. 

In  some  countries,  recourse  is  had  to  fire,  as  an  amender 
of  the  soil :  this  process,  called  burning,  is  strongly  recom- 
mended by  some  practical  farmers,  and  highly  disapproved 
of  by  others :  both  sides  rely  on  the  test  of  their  own  ex- 
perience; and  both  are  so  sincere  in  their  opinions, 
that  it  would  be  useless  to  contest  the  truth  of  their  ob- 
servations. I  can  only  agree  with  each  of  these  contra- 
dictory opinions,  and  at  the  same  time  make  known  the 
cases  to  which  burning  is  applicable,  and  those  to  which 
it  is  unsuited,  in  order  to  enlighten  the  agriculturist  as  to 
the  effect  of  the  operation  :  he  can  afterwards  make  for 
himself  just  and  rational  applications  of  the  theory. 

In  the  process  of  burning,  a  layer  of  from  two  to  four 
inches  in  thickness,  is  removed  from  the  soil  in  clods : 
little  heaps  of  combustibles  are  formed  with  the  broom, 
thistles,  fern,  and  shrubs  that  grow  upon  the  spot :  these 
are  covered  with  the  clods,  and  at  the  end  of  some  days 
are  set  on  fire ;  the  combustion  of  them  lasts  a  longer  or 
shorter  time.  When  the  whole  has  become  cool,  the  heaps 
of  ashes  are  spread  over  the  surface,  and  thus  mixed  with 
the  soil. 

By  this  operation  the  constituent  parts  of  a  soil  are  di- 
vided, and  rendered  less  compact ;  the  disposition  which 
a  clayey  ground  has  to  absorb  a  great  quantity  of  water,  is 
corrected,  and  this  soil  rendered  less  cohesive  and  pasty; 
the  inactive  vegetable  matter  contained  in  it,  is  converted 
into  manure  :    the  oxidation  of  its   iron  is  carried  to  its 


IMPROVEMENT    OF    THE    SOIL.  115 

maximum ;  and  insects  and  the  seeds  of  injurious  plants 
are  destroyed.  Hence  we  perceive  that  burning  belongs 
to  moist,  compact  soils;  it  is  attended  with  good  effects 
when  the  bed  of  earth  is  too  cohesive,  or  when  it  presents 
veins  of  blackish  oxide  of  iron :  it  is  suited  to  nearly  all 
cold  and  compact  lands. 

Burning,  especially  if  it  be  judiciously  conducted,  com- 
pletely changes  the  nature  of  a  soil,  and  corrects  the  great- 
er part  of  its  imperfections.  I  have  by  this  means  given  to 
agriculture  120  acres  of  land  reputed  sterile,  formed  almost 
entirely  of  a  ferruginous  and  very  compact  clay :  the  burn- 
ing extended  to  the  depth  of  four  inches.  For  twelve  years 
this  land,  though  not  very  productive,  has  afforded  me  good 
returns.  Its  former  sterility  had  procured  it  the  name  of 
the  Jews^  heath. 

Burning  is  hurtful  to  calcareous  and  light  lands;  to 
soils  of  which  the  composition  is  perfect;  and  to  fertile 
lands,  rich  in  decomposed  animal  and  vegetable  sub- 
stances. 

It  is  useless  to  soils  purely  siliceous,  for  these  can  receive 
no  modification  from  fire. 

In  some  countries  it  is  customary  to  burn  the  stubble 
upon  the  field;  this  method,  which  is  only  an  imperfect 
mode  of  burning,  is  productive  of  good  in  two  ways ;  in 
the  first  place,  it  purifies  the  soil  from  insects,  and  from  the 
seeds  of  noxious  plants ;  and  in  the  second  place,  it  forms  a 
thin  layer  of  carbon,  which  by  its  extreme  division  is  capa- 
ble of  being  easily  absorbed  by  plants.  I  believe  that  even 
the  heat  occasioned  by  the  combustion  of  the  stubble  and 
herbs  covering  the  soil,  may  produce  salutary  changes  in 
the  combinations  of  the  constituent  parts. 

The  results  which  I  obtained  from  mixing  calcined  clay 
with  the  sand  constituting  the  soil  upon  a  portion  of  the 
plain  of  Sablons,  near  Paris,  has  led  me  to  think,  that 
whenever  lands  of  this  nature  are  cultivated,  it  may  be 
useful  to  amend  them  by  the  same  process :  in  order  to  do 
this,  clay  may  be  formed  into  balls  by  moistening  it  with 
water  enough  to  reduce  it  to  a  paste;  these  balls,  after 
having  been  calcined  in  a  lime-kiln,  or  the  oven  of  a  pot- 
tery, may  be  pounded,  and  the  fragments  mixed  with  the 
Boil.  Calcareous,  siliceous,  and  sandy  soils  may  be  in  this 
way  much  improved. 

Of  all  the  agents  which  may  be  employed  as  amend- 
ments, there  is  none  of  v/hich  the  action  is  more  powerful 


116  CHYMISTRY    APPLIED    TO    AGRICULTURE: 

than  that  of  water :  not  only  does  it  contribute  to  the 
nourishment  of  the  plant  by  its  decomposition,  which  de- 
posits in  the  vessels  its  elementary  principles ;  but  it  acts 
still  farther  by  promoting  the  fermentation  of  manures, 
and  by  conveying  into  the  vegetable  organs  the  juices 
and  salts.  Independently  of  these  properties,  water  di- 
lutes the  sap,  which  has  become  thickened  in  the  body  of 
the  plant,  and  facilitates  its  circulation ;  and  likewise  fur- 
nishes abundantly  the  means  of  transpiration.  The  soil  is 
also  softened  by  water,  and  thus  rendered  more  permeable 
by  the  roots,  and  by  atmospheric  air  which  supplies  them 
with  the  moisture  it  contains. 

All  the  excess  of  water  absorbed  by  plants,  is  thrown 
off  by  transpiration ;  and  this  transpiration  is  always  more 
or  less  abundant  in  proportion  to  the  quantity  imbibed. 

The  custom  of  inundating  meadows  during  winter,  pre- 
serves them  from  the  effects  of  hard  frosts.  Davy  ascer- 
tained the  temperature  beneath  the  bed  of  ice  covering  a 
meadow,  and  above  it:  beneath  the  ice  his  thermometer 
stood  at  43° ;  above  the  ice  at  29°.  Every  one  must  have 
observed,  that  when  the  surface  of  a  meadow  is  only  par- 
tially covered  by  water  during  the  winter,  the  herbage 
upon  that  part  which  is  left  dry,  is  withered  and  nearly 
dead,  whilst  the  rest  retains  its  green  hue,  and  continues 
to  grow. 

The  character  of  water  used  for  irrigation,  is  a  thing  of 
some   consequence;    that  of  a  living  stream   is  the    beg* 
especially  i^  it  have,  by  a  long  course,  become  impregnated 
with  a  gopa  quantity  of  atmospheric  air. 

Though  water  is  the  most  active  agent  in  vegetation,  it 
is  nevertheless  necessary  to  apply  it  with  reserve  and  cau- 
tion :  the  worst  effects  are  produced  by  irrigating  land  so 
often  as  to  keep  the  soil  constantly  in  the  state  of  a  liquid 
paste.  The  first  evil  arising  from  such  a  course  is  that  of 
increasing  the  size  of  the  plants  to  the  injury  of  all  their 
other  qualities ;  for  in  such  a  case  the  fibres  of  plants  be- 
come loose ;  the  texture  soft  and  watery ;  the  flowers  are 
inodorous,  and  the  fruits  without  firmness,  taste,  or  perfume. 
The  second  is,  that  all  useful  plants  which  do  not  require 
much  water,  give  place  to  rushes  and  flags,  which  change 
and  ruin  the  soil :  in  this  case  the  same  evil  is  produced 
which  we  seek  to  destroy  in  wet  lands  by  the  use  of  soot, 
gravel,  ashes,  and  other  absorbing  and  saline  bodies. 

Frequent  irrigations  are    not    injurious    to    poor,  light, 


IMPROVEMENT    OF    THE    SOIL.  IIT 

sandy,  or  calcareous  soils,  which  have  much  depth;  but 
they  are  injurious  to  rich,  compact,  argillaceous  soils;  for 
in  such  the  noxious  plants  of  which  I  have  just  spoken, 
readily  establish  themselves. 

To  ascertain  the  most  favorable  times  for  irrigation,  it 
is  necessary  to  consult  the  state  of  the  soil,  and  of  the 
plants ;  when  the  earth  is  deprived  of  moisture  to  such  a 
depth  that  the  plants  languish,  and  begin  to  lose  their 
leaves,  the  favorable  moment  has  arrived  for  watering 
them.  If  allowed  to  remain  in  this  state  too  long,  they 
cease  to  grow,  and  hasten  to  terminate  their  vegetation  by 
the  production  of  fruits  and  flowers ;  but  these  are  always 
feeble,  poor,  and  incomplete,  when  produced  under  such 
circumstances. 

The  custom  of  allowing  lands  to  lie  fallow  after  having 
produced  several  harvests,  has  descended  from  the  re- 
motest antiquity,  and  is  still  followed  in  the  greatest  part 
of  Europe.  It  has  been  thought  necessary,  that  land,  after 
having  been  exhausted  by  two  or  three  successive  crops, 
should  be  allowed  to  rest,  or  to  remain  in  fallow  during 
one  or  two  years,  in  order  that  it  might  have  time  to  re- 
cover its  strength,  or  productive  virtue.  The  necessity 
for  rest,  imposed  by  nature  upon  all  animals  after  con- 
tinued action,  undoubtedly  gave  rise  to  this  practice;  and 
though  the  supposed  analogy  between  living  bodies,  and 
those  that  are  not  so,  has  no  rational  foundation,  yet  it  has 
confirmed  the  custom  of  fallowing  which  arose  from  it. 

However,  I  am  far  from  believing  that  this  was  the  only 
cause  for  the  adoption  of  the  method  of  which  I  am 
speaking :  I  believe  that  it  may  be  attributed  to  the  want 
of  hands  for  performing  the  labor  of  constant  cultivation, 
or  to  the  impossibility  of  nourishing  a  sufllcient  number  of 
animals  to  furnish  the  necessary  manures. 

The  extent  to  which  the  cultivation  of  lands  should  be 
carried,  ought  always  to  be  in  proportion  to  the  popula- 
tion to  be  fed  by  its  products.  It  is  to  be  presumed,  that 
when  the  globe  had  fewer  inhabitants,  the  settlements 
were  made  in  those  spots  where  the  soil  was  most  fertile, 
and  that  when  these  were  exhausted,  they  removed  else- 
where ;  but  when  property  came  to  be  divided  and  marked 
out,  each  cultivator  confined  his  labors  to  such  a  por- 
tion of  land  as  would  supply  his  wants:  so  that  when  it 
was  sufficient  for  him  to  cultivate  one  quarter,  or  one 
third  of  his  territory,  he  allowed  the  rest  to  remain  un- 
tilled. 


118  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Fallowing  has,  according  to  this  view  of  the  subject, 
arisen  from  necessity.  We  know  with  certainty  that  the 
crops  in  gardens  surrounding  dwellings  may  be  multiplied 
and  continued  indefinitely,  by  means  of  tilling  and  manur- 
ing ;  but  the  necessity  for  this  is  not  felt,  as  long  as  the  prod- 
uce is  sufficient  for  consumption,  and  when  the  expense 
attending  the  means  of  procuring  an  increase  beyond  that, 
would  be  so  much  clear  loss. 

In  proportion  as  population  has  increased,  lands  have 
been  cleared  up,  and  cultivation  extended  and  improved ;  so 
that  production  has  always  kept  pace  with  consumption. 
As  the  wants  of  society  permit  fallowing  less  at  this  time 
than  formerly,  it  has  begun  to  disappear,  especially  where 
those  wants  are  most  pressing ;  and  more  particularly,  when 
there  is  an  assured  prospect  of  an  advantageous  market  for 
agricultural  productions. 

Fallowing  was  necessary  as  long  as  grains  only,  all  of 
which  exhaust  the  soil,  were  cultivated  ;  during  the  intervals 
of  tilling  the  fields,  a  variety  of  herbs  grew  in  them, 
which  afforded  food  for  animals,  and  the  roots  of  which, 
when  buried  in  the  soil  by  the  plough,  furnished  a  great 
part  of  the  necessary  manure.  But  at  this  day,  when  we 
have  succeeded  in  establishing  the  cultivation  of  a  great 
variety  of  roots  and  artificial  grasses,  the  system  of  fallow- 
ing can  be  no  longer  supported  by  the  shadow  of  a  good 
reason. 

The  scarcity  of  dung  occasioned  by  the  limited  number 
of  cattle  that  could  be  maintained  upon  a  farm,  caused  the 
custom  of  fallowing  to  be  continued ;  but  the  ease 
witTi  which  fodder  may  be  cultivated  furnishes  the  means 
of  supportijig  an  lincreased  number  of  animals ;  these  in 
their  turn  supply  manure  and  labor;  and  the  farmer  is  no 
longer  under  the  necessity  of  allowing  his  lands  to  lie 
fallow. 

Artificial  grass  lands  ought  now  to  be  considered  as 
forming  the  basis  of  agriculture ;  these  furnish  fodder,  the 
fodder  supports  cattle,  and  the  cattle  furnish  manure,  labor, 
and  all  the  means  necessary  to  a  thorough  system  of  culti- 
vation. 

The  suppression  of  the  practice  of  fallowing  is  then 
equally  serviceable  to  the  cultivator,  who  increases  his  pro- 
ductions without  proportionally  increasing  his  expenses,  and 
to  society,  which  derives  from  the  same  extent  of  soil  a 
much  greater  quantity  of  food,  and  additional  resources  for 
supplying  the  work-shops  of  the  manufacturer. 


IMPROVEMENT    OF   THE    SOIL.  119 

A  great  advantage  has  arisen  from  the  system  of  a  ro- 
tation of  crops,  which  has  succeeded  that  of  fallowing. 
By  skilfully  arranging  a  succession  of  crops  of  grain, 
artificial  fodder,  leguminous  plants,  roots,  &lc.,  the  earth 
is  enriched,  instead  of  being  impoverished;  the  ground 
is  cleansed  from  weeds,  and  more  abundant  crops  are  ob-  - 
tained  at  a  less  expense.  During  those  years  when  cer 
tain  fodders,  such  as  clover,  sainfoin,  and  trefoil,  require 
no  other  care  than  that  of  harvesting  them,  the  farmer 
•can  bestow  all  his  attention,  manures,  and  the  labor  o' 
his  cattle,  upon  such  other  portions  of  his  farm  as  may 
need  amelioration ;  so  that,  instead  of  having  one  third 
of  his  land  lying  as  an  unproductive  fallow,  it  may  be 
covered  with  herbage  affording  the  finest  food  for  cattle. 
The  soil  will  be  growing  richer  instead  of  poorer,  and  may 
be  prepared  for  raising  grain,  without  the  addition  of  any 
manure. 

What  has  contributed  the  most  towards  confining  French 
agriculture  to  that  state  of  mediocrity,  from  which  neither 
the  examples  nor  the  writings  of  many  enlightened  theo 
retical  farmers  have  been  able  to  raise  it,  is  the  passion 
for  cultivating  too  large  an  extent  of  land,  with  limited 
powers  as  to  its  arrangement.  Where  all  the  land  is  sown 
without  any  portion  of  it  being  properly  prepared,  the 
ground  is  exhausted  instead  of  being  improved  by  cultiva- 
tion. The  farmer,  who  takes  land  upon  lease,  has  no 
interest  in  endeavoring  to  make  it  better,  because  the 
shortness  of  the  lease  does  not  permit  him  to  enjoy  the  fi-uit 
of  his  labor ;  he  is  forced  to  reap  from  the  land  all  it  will 
produce. 

Instead  of  including  in  his  plans  of  cultivation  a  space 
of  ground  disproportioned  to  the  means  which  are  at  his 
disposal,  the  intelligent  farmer  will  at  first  occupy  himself 
only  with  such  a  portion  of  his  land  as  will  be  sufficient  for 
his  cattle,  his  manures,  and  his  improvements ;  when  this 
has  been  brought  into  a  good  state  of  cultivation,  and  a 
regular  succession  of  crops  established  upon  it,  he  can 
carry  his  amendments  over  successive  portions,  till,  in  a  few 
years,  the  whole  soil  may  be  brought  to  yield  every  thing 
which  it  is  capable  of  producing.  But  it  is  only  by  long 
leases,  that  a  farmer  can  be  enabled  to  pursue  a  method  so 
wise  and  so  secure ;  and  long  leases  would  be  in  all  re- 
spects as  much  for  the  interest  of  the  proprietor  as  of  the 
farmer. 


120  CHYMISTRY    APPLIED    TO   AGRICULTURE. 

As  the  estate  which  T  own  is  very  extensive,  I  have  not 
hesitated  to  set  apart  from  my  regular  rotation  of  crops, 
about  two  hundred  and  fifty  acres  of  land  of  middling  qual- 
ity, which  had  every  year  been  manured  equally  with  my 
best  lands,  but  which  had  yielded  but  poor  returns.  This 
great  extent  of  land  is  now  laid  down  to  grass,  and  serves 
as  a  pasture  for  irjy  cows,  oxen,  and  sheep :  each  year  I 
break  up  one  fifth  part  of  it,  and  sow  it  with  oats,  rye,  or  bar- 
ley, and  the  following  year  reestablish  it  as  a  grass  land.  I 
am  convinced  that  this  land  would  never  have  repaid  me  for 
the  expense  attendant  upon  raising  from  it  successive  crops 
of  grain,  roots,  and  legumes. 


CHAPTER  VII. 

OF    THE    SUCCESSION    OP    CROPS. 

A  SOIL  may  be  forced,  by  extreme  care,  enormous  ex- 
pense, and  the  use  of  manure  without  measure,  to  produce 
all  sorts  of  crops ;  but  it  is  not  in  such  sort  of  proceedings 
ihat  the  science  of  agriculture  consists.  Agriculture  ought 
not  to  be  considered  as  an  object  of  luxury  ;  and  whenever 
the  produce  of  agricultural  management  does  not  amply 
repay  the  care  and  expense  bestowed  upon  it,  the  system 
followed  is  bad. 

A  good  agriculturist  will,  in  the  first  place,  make  himself 
acquainted  with  the  nature  of  his  soil,  in  order  to  know  the 
kind  of  plants  to  which  it  is  best  adapted  :  this  knowledge 
may  be  easily  acquired  by  an  acquaintance  with  the  species 
of  the  plants  produced  upon  it  spontaneously,  or  by  experi- 
ments made  upon  the  land,  or  upon  analogous  soils  jn  the 
neighbourhood. 

But  however  well  adapted  the  soil  and  climate  may  be 
to  the  cultivation  of  any  particular  kind  of  vegetable,  the 
former  soon  ceases  to  be  productive,  if  constantly  appro- 
priated to  the  culture  of  plants  of  the  same  or  analogous 
species.  In  order  that  land  may  be  cultivated  success- 
fully, various  kinds  of  vegetables  must  be  raised  upon  it 
in  succession,  and  the  rotation  must  be  conducted  with 
intelligence,  that  none  unsuited  either  to  the  soil  or  cli- 
mate may  be  introduced.      It  is  the  art  of  varying  the 


SUCCESSION    OF    CROPS.  121 

crops  upon  the  same  soil,  of  causing  different  vegetables 
tQ  succeed  one  another,  and  of  understanding  the  effect 
of  each  upon  the  soil,  that  can  alone  establish  that  good 
order  of  succession  which  constitutes  cropping. 

A  good  system  of  cropping  is,  in  my  opinion,  the  best 
guarantee  of  success  that  the  farmer  can  have ;  without 
this,  all  is  vague,  uncertain,  and  hazardous.  In  order  to 
establish  this  good  system  of  cropping,  a  degree  of  knowl- 
edge is  necessary,  which  unhappily  is  wanting  to  the 
greater  part  of  our  practical  farmers.  I  shall  here  state 
certain  facts  and  principles,  which  may  serve  as  guides  in 
this  important  branch  of  agriculture. 

More  extensive  information  upon  this  subject  may  be 
found  in  the  excellent  works  of  Messrs.  Yvart  and  Pictet.* 

Principle  1.     All  plants  exhaust  the  soil. 

Plants  are  supported  by  the  earth,  the  juices,  with  which 
this  is  impregnated  forming  their  principal  aliment.  Water 
serves  as  the  vehicle  for  conveying  these  juices  into  the 
organs,  or  presenting  them  to  the  suckers  of  the  roots  by 
which  they  are  absorbed  ;  thu-s  the  progress  of  vegetation 
tends  constantly  to  impoverish  the  soil,  and  if  the  nutritive 
juices  in  it  be  not  renewed,  it  will  at  length  become  per- 
fectly barren. 

A  soil  well  furnished  with  manure  may  support  several 
successive  crops,  but  each  one  will  be  inferior  to  the  pre- 
ceding, till  the  earth  is  completely  exhausted. 

Principle  2.     All  plants  do  not  exhaust  the  soil  equally. 

Plants  are  nourished  by  air,  water,  and  the  juices  con- 
tained in  the  soil ;  but  the  different  kinds  of  plants  do  not 
require  the  same  kinds  of  nourishment  in  equal  degrees. 
There  are  some  that  require  to  have  their  roots  constantly 
in  water  ;  others  are  best  suited  with  dry  soils ;  and  there 
are  those  again,  that  prosper  only  in  the  best  and  most 
richly  manured  land. 

The  grains  and  the  greater  part  of  the  grasses  push  up 
long  stalks,  in  which  the  fibrous  principle  predominates; 
these  are  garnished  at  the  base  by  leaves,  the  dry  texture 
and '  small  surface  of  which  do  not  permit  them  to  absorb 
much  either  of  air  or  water ;  the  principal  nourishment  is 
absorbed  from  the  ground  by  their  roots  ;  their  stalks  fur- 
nish  little  or   no  food   for   animals  ;    so  that  these  plants 

*  "  Cours  complet  d' Agriculture,"  articles  AssolcTneiU  et  Succession 
de  CvUure,  pau-  Yvart.  —  "  Traite  de  Assolemens,"  par  Ch.  Pictet. 
11 


122  CHYMISTRY    APPLHED    TO    AGKlCULTUItE. 

exhaust  the  soil,  without  sensibly  repairing  the  loss,  either 
by  their  stalks,  which  are  cut  to  be  applied  to  a  particular 
use,  or  by  their  roots,  which  are  all  that  remain  in  the 
ground,  and  which  are  dried  and  exhausted  in  completing 
the  process  of  fructification. 

Those  pknta,  on  the  contrary,  that  are  provided  with 
large,  fleshy,  porous,  green  leaves,  imbibe  from  the  atmo- 
sphere carbonic  acid  and  water,  and  receive  from  the  earth 
the  other  substances  by  which  they  are  nourished.  If 
these  are  cut  green,  the  loss  of  juices  which  the  soil  has 
sustained  by  their  growth,  is  less  sensibly  felt,  as  a  part 
of  it  is  compensated  for  by  their  roots.  Nearly  all  the 
plants  that  are  cultivated  for  fodder  are  of  this  kind. 

There  are  some  plants,  which,  though  generally  raised 
for  the  sake  of  their  seed,  exhaust  the  soil  less  than  the 
grains ;  these  are  of  the  numerous  family  of  leguminous 
plants,  and  which  sustain  a  middle  rank  between  the  two 
of  which  I  have  just  spoken.  Their  perpendicular  roots 
divide  the  soil,  and  their  large  leaves,  and  thick,  loose, 
porous  stalks  readily  absorb-  air  and  water.  These  parts 
preserve  for  a  long  time  the  juices  with  which  they  are 
impregnated,  and  yield  them  to  the  soil,  if  the  plant  be 
buried  in  it  before  arriving  at  maturity ;  when  this  is 
done,  the  field  is  still  capable  of  receiving  an<i  nourish- 
ing a  good  crop  of  corn.  Beans  produce  this  effect  in  a 
remarkable  degree ;  peas  to  a  less  extent. 

Generally  speaking,  those  plants  that  are  cut  green,  or 
whilst  in  flower,  exhaust  the  soil  but  little ;  till  this  period 
they  have  derived  their  support  almost  exclusively  from  the 
air,  earth,  and  water  ;  their  stalks  and  roots  are  charged 
with  juices,  and  those  parts  that  are  left  in  the  earth  after 
mowing,  will  restore  to  it  all  that  had  been  received  from 
it  by  the  plant. 

From  the  time  when  the  seed  begins  to  be  formed,  the 
whole  system  of  nourishment  is  changed ;  the  plant  con- 
tinues to  receive  nourishment  for  the  perfecting  of  its 
seed,  from  the  atmosphere  and  the  earth,  and  also  yields 
to  the  grain  all  the  juices  it  had  secreted  in  its  own  stalks 
and  roots :  by  this  means  the  stalks  and  roots  are  dried 
and  exhausted.  When  the  fruits  have  arrived  at  maturity 
the  skeleton  remains  of  the  plant,  if  abandoned  to  the 
earth,  restore  to  it  only  a  small  portion  of  what  had  been 
taken  from  it. 

The  oleaginous  seeds  exhaust  the  soil  more  than  the  fa- 


•SUCCESSION    OF    CROPS.  123 

rinaceous  seeds ;  and  the  agriculturist  cannot  be  at  too 
much  pains  to  free  his  grounds  from  weeds  of  that  nature^ 
which  so  readily  impoverish  them^  especially  from  the 
wild  mustard,  sinapis  arvensis.,  with  which  cultivated  fields 
are  so  often  covered. 

Principle  3.  Plants  of  different  kinds  do  not  exhctust 
a  soil  in  the  same  manner. 

.  The  roots  of  plants  of  the  same  genus  or  family,  grow 
in  the  soil  in  the  same  manner ;  they  penetrate  to  a  simi- 
lar depth,  and  extend  to  corresponding  distances,  and  ex- 
haust all  that  portion  of  the  soil  with  which  they  come  in 
contact. 

Those  roots  which  lie  nearest  the  surface,  are  more  di- 
vided than  those  that  -penetrate  deeply.  The  spindle  or 
tap  roots,  and  all  those  that  penetrate  deeply  into  the  earth, 
throw  out  but  few  radicles  near  the  surface,  and  conse- 
quently the  plant  is  supplied  with  nourishment  from  the 
layers  of  soil  in  contact  with  the  lower  part  of  the  root. 
Of  the  truth  of  this  I  have  often  had  proof,  and  I  will 
mention  an  example.  If,  when  a  beet  or  turnip  is  trans- 
planted, the  lower  portion  of  the  spindle  be  cut  off,  it  will 
not  grow  in  length,  but  in  order  to  obtain  its  supplies  of 
nourishment  from  the  soil,  it  will  send  out  radicles  from 
its  sides,  which  will  enable  it  to  obtain  the  necessary  sup- 
plies from  the  upper  layers  of  the  soil ;  and  the  root  wiM 
become  roundish  instead  of  long. 

Plants  exhaust  only  that  portion  of  the  soil  which  comes 
in  contact  with  their  roots  ;  and  a  spindle  root  may  be  able 
to  draw  an  abundance  of  nourishment  from  land,  the  sur- 
face of  which  has  been  exhausted  by  short  or  creeping 
roots. 

The  roots  of  plants  of  the  same  and  of  analogous  spe- 
cies always  take  a  like  direction,  if  situated  in  a  soil 
which  allows  them  a  free  developement ;  and  thus  they  pass 
through,  and  are  supported  by,  the  same  layers  of  earth. 
For  this  reason  we  seldom  find  trees  prosper  that  take  the, 
place  of  others  of  the  same  species ;  unless  a  suitable  pe- 
riod has  been  allowed  for  producing  the  decomposition  of 
the  roots  of  the  first,  and  thus  supplying  the  earth  with 
iresh  manure. 

To  prove  that  different  kinds  of  plants  do  not  exhaust 
the  soil  in  the  same  manner,  it  is  perhaps  sufficient  for  me 
to  state,  that  the  nutrition  of  vegetables  is  not  a  process 
altogether  mechanical;   that   plants  do  not   absorb   indis- 


124  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

criminately,  nor  in  the  same  proportions,  all  the  juices  and 
salts  that  are  presented  to  them;  but  that  either  vitality, 
or  the  conformation  of  their  organs,  exerts  an  influence 
over  the  nutritive  action ;  that  there  is  on  the  part  of 
plants  some  taste,  some  choice  regarding  their  food,  as  has 
been  sufficiently  proved  by  the  experiments  of  Messrs. 
Davy  and  de  Saussure.  It  is  with  plants  as  it  is  vi^ith  ani- 
mals, there  are  some  elements  common  to  all,  and  some 
peculiar  to  each  kind  :  this  is  placed  beyond  doubt,  by 
the  preference  given  by  some  plants  to  certain  salts,  over 
others. 

Principle  4.  All  plants  do  not  restore  to  the  soil  either 
the  same  quantity  or  the  same  quality  of  manure. 

The  plants  that  grovvr  upon  a  soil,  exhaust  more  or  less 
of  its  nutritive  juices,  but  all  return  to  it  some  remains,  to 
repair  a  part  of  its  loss.  The  grains  and  the  oleaginous 
seeds  may  be  placed  at  the  head  of  those  vi^hich  exhaust 
a  soil  the  most,  and  repair  the  least  the  injury  done  it.  In 
those  countries  where  plants  are  plucked  up,  they  return 
nothing  to  the  soil  that  has  nourished  them.  There  are 
some  plants,  to  be  sure,  besides  those  mentioned  above, 
that  by  forming  their  seed  consume  a  great  part  of  the 
manure  contained  in  the  soil ;  but  the  roots  of  many  of 
these  soften  and  divide  the  soil  to  a  considerable  depth ; 
and  the  leaves  which  fall  from  the  stalk  during  the  prog- 
ress of  vegetation  restore  to  the  earth  more  than  is  re- 
turned by  those  before  mentioned.  There  are  others  still, 
the  roots  and  stalks  of  which  remaining  strong  and  succu- 
lent after  the  production  of  their  fruits,  restore  to  the  soil 
a  portion  of  the  juices  they  had  received  from  it ;  of  this 
kind  are  the  leguminous  plants. 

Many  plants  that  are  not  allowed  to  produce  seed  ex- 
haust the  soil  but  very  little ;  these  are  very  valuable  in 
forming  a  system  of  successive  crops,  as  by  introducing 
them  into  the  rotation,  ground  may  be  made  to  yield  for 
many  years  without  the  application  of  fresh  manure ;  the 
varieties  of  trefoil,  especially  clover  and  sainfoin,  are  of 
this  sort. 

Principle  5.     All  plants  do  not  foul  the  soil  equally. 

It  is  said  that  a  plant  fouls  the  soil,  when  it  facilitates  or 
permits  the  growth  of  weeds,  which  exhaust  the  earth, 
weary  the  plant,  appropriate  to  themselves  a  part  of  its 
nourishment,  and   hasten  its  decay.      All  plants  not  pro* 


SUCCESSION    OF    CROPS,  135 

vided    with    an    extensive    system    of  large    and    vigorous 
leaves,  calculated  to  cover  the  ground,  foul  the  soil. 

The  grains,  from  their  slender  stalks  rising  into  the  air, 
and  their  long,  narrow  leaves,  easily  admit  into  their  inter- 
vals those  weeds  that  grow  upon  the  surface,  which,  being 
defended  from  h^at  and  winds,  grow  by  favor  of  the  grain 
they  injure. 

Herbaceous  plants,  on  the  contrary,  which  cover  the 
surface  of  the  soil  with  their  leaves,  and  raise  their  stalks  to 
only  a  moderate  height,  stifle  all  that  endeavours  to  grow  at 
their  roots,  and  the  earth  remains  clean.  It  must  be  ob- 
served, however,  that  this  last  is  not  the  case  unless  the 
soil  be  adapted  to  the  plants,  and  contain  a  sufficient  quan* 
tity  of  manure  to  support  them  in  a  state  of  healthy  and 
vigorous  vegetation :  it  is  for  want  of  these  favorable  cir- 
cumstances that  we  often  see  these  same  plants  languish- 
ing, and  allowing  the  growth  of  less  delicate  herbs,  which 
cause  them  to  perish  before  their  time.  Vegetables  sown 
and  cultivated  in  furrows,  as  are  the  various  roots  and  the 
greater  part  of  the  leguminous  plants,  allow  room  for  a 
large  number  of  weeds ;  but  the  soil  can  be  easily  kept 
free  by  a  frequent  use  of  the  hoe  or  weeding  fork;  and  by 
this  means  may  be  preserved  rich  enough  for  raising  a 
second  crop,  especially  if  the  first  be  not  allowed  to  go  to 
seed. 

The  seeds  that  are  committed  to  the  ground  ofterl  con- 
tain those  of  weeds  amongst  them,  and  too  much  care 
cannot  be  taken  to  avoid  this :  it  is  more  frequently  the 
case,  however,  that  these  are  brought  by  the  winds,  depos- 
ited by  water,  or  sown  with  the  manure  of  the  farm-yard. 

The  carelessness  of  those  agriculturists  who  allow  this 
ties  and  other  hurtful  plants  to  remain  in  their  fields,  can- 
not be  too  much  censured;  each  year  these  plants  produce 
new  seeds,  thus  exhausting  the  land  and  increasing  their 
own  numbers,  till  it  becomes  almost  impossible  to  free  the 
soil  from  them.  This  negligence  is  carried  by  some  to 
such  an  extent,  that  they  will  reap  the  grain  all  around  the 
thistles,  and  leave  them  standing  at  liberty  to  complete 
their  growth  and  fructification.  How  much  better  it  would 
be  to  cut  those  hurtful  plants  before  they  flower,  and  to  add 
them  to  the  manure  of  the  farm.  From  the  principles 
which  I  have  just  established,  we  may  draw  the  following 
coQciusions. 

n» 


126  CHYMISTRY    APPLIED    TO    AGKICULTURE. 

1st.  That  however  well  prepared  a  soil  may  be,  it  can- 
not nourish  a  long  succession  of  crops  without  becoming 
exhausted. 

2d.  Each  harvest  impoverishes  the  soil  to  a  certain  ex- 
tent, depending  upon  the  degree  of  nourishment  which  it 
restores  to  the  earth. 

3d.  The  cultivation  of  spindle  roots  ought  to  succeed 
that  of  running  and  superficial  roots. 

4th.  It  is  necessary  to  avoid  returning  too  soon  to  the 
cultivation  of  the  same  or  of  analogous  kinds  of  vegetables, 
in  the  same  soil.* 

5th.  It  is  very  unwise  to  allow  two  kinds  of  plants, 
which  admit  of  the  ready  growth  of  weeds  among  them,  to 
be  raised  in  succession. 

6th.  Those  plants  that  derive  their  principal  support 
from  the  soil  should  not  be  sown,  excepting  when  the  soil  is 
sufficiently  provided  with  manure. 

7th.  When  the  soil  exhibits  symptoms  of  exhaustion 
from  successive  harvests,  the  cultivation  of  those  plants  that 
restore  most  to  the  soil,  must  be  resorted  to. 

These  principles  are  confirmed  by  experience;  they 
form  the  basis  of  a  system  of  agriculture  rich  in  its  prod- 
ucts, but  more  rich  in  its  economy,  by  the  diminution  of 
the  usual  quantity  of  labor  and  manure.  All  cultivators 
ought  to  be  governed  by  them,  but  their  application  must  be 
modified  by  the  nature  of  soils  and  climates,  and  the  par- 
ticular wants  of  each  locality. 

To  prescribe  a  series  of  successive  and  various  harvests, 
without  paying  any  regard  to  the  difference  of  soils,  would 
be  to  commit  a  great  error,  and  lo  condemn  the  system  of 
cropping  in  the  eyes  of  those  agriculturists,  who  are  too 
little  enlightened  to  think  of  introducing  into  their  grounds 
the  requisite  changes. 

Clover  and  sainfoin  are  placed  amongst  the  vegetables 

*  In  addition  to  the  reasons  I  have  given  why  plants  of  the  same  or 
analogous  kinds  should  not  be  cultivated  in  succession  upon  the  same 
soil,  there  is  another  which  I  will  here  assign.  M.  Olivier,  member 
of  the  French  Institute,  has  described  with  much  care  all  the  insects 
which  devour  the  neck  of  the  roots  of  grain  ;  these  multiply  infinitely, 
if  the  same  or  analogous  kinds  of  plants  be  presented  to  the  soil  for 
several  successive  years  ;  but  perish  for  want  of  food,  whenever  plants 
not  suited  to  be  food  for  their  larvte,  are  made  to  succeed  the  grains. 
These  insects  belong  to  the  family  of  Tipulas,  or  to  that  of  flies.  — 
(Sixteenth  Vol.  of  the  Memoirs  of  the  Royal  and  Central  Agricultural 
Society  of  Paris.) 


SUCCESSION    OP    CROPS.  127 

that  ought  to  enter  into  the  system  of  cropping,  but  these 
plants  require  a  deep  and  not  too  compact  soil,  in  order  that 
their  roots  may  fix  themselves  firmly. 

Flax,  hemp,  and  corn  require  a  good  soil,  and  can  be 
admitted  as  a  crop  only  upon  those  lands  that  are  fertile 
and  well  prepared. 

Light  and  dry  soils  cannot  bear  the  same  kind  of  crop  as 
those  that  are  compact  and  moist. 

Each  kind  of  soil,  then,  requires  a  particular  system  of 
crops,  and  each  farmer  ought  to  establish  his  own  upon  a 
perfect  knowledge  of  the  character  and  properties  of  the 
land  he  cultivates. 

As  in  each  locality  the  soil  presents  shades  of  differ- 
ence, more  or  less  marked,  according  to  the  exposure, 
composition,  depth  of  the  soil,  &/C.,  the  proprietor  ought 
so  to  vary  his  crops,  as  to  give  to  each  portion  of  the  land 
the  plants  for  which  it  is  best  adapted  ;  and  thus  establish  a 
particular  rotation  of  crops  upon  the  several  divisions  of  his 
estate. 

The  wants  of  the  neighbourhood,  the  facility  with  which 
the  products  may  be  disposed  of,  and  the  comparative  value 
of  the  various  kinds  of  crops,  should  all  be  taken  into  the 
calculation  of  the  farmer,  in  forming  his  plan  of  proceed- 
ings. 

In  England  and  some  of  the  northern  countries,  the  cul- 
tivation of  barley  returns  frequently  in  their  successive 
crops,  because  the  number  of  breweries  afford  a  sure  mar- 
ket for  that  grain.  In  Belgium,  Russia,  and  upon  the  bor- 
ders of  the  Rhine,  rye  is  generally  cultivated  on  account  of 
immense  distilleries  of  spirit :  the  wants  of  the  great  num- 
bers of  animals  that  are  supplied  by  the  malt  and  refuse  of 
these  works,  gives  every  encouragement  for  the  cultivation 
of  that  particular  kind  of  grain. 

The  cultivation  of  woad  and  madder  would  be  more  ad- 
vantageous in  the  vicinity  of  great  manufactories,  where 
coloring  is  executed,  than  in  those  countries  which  afford 
no  consumption  of  these  articles.  In  France,  where  the 
abundance  and  low  price  of  wine  will  not  permit  us  to  hope 
for  any  market  for  beer;  in  France,  where  the  greatest  por- 
tion of  the  people  live  principally  upon  bread  made  from 
wheat,  that  grain  is  cultivated  everywhere,  where  it  can  be 
made  to  grow ;  only  the  inferior  soils  are  appropriate  to  the 
cultivation  of  other  grains. 

There  is  another  point  in  regard  to  crops  that  ought  to 


128  CHYMISTRY    APPLIED    TO   AGRICULTURE. 

be  well  weighed  by  the  farmer :  though  his  lands  may  be 
suited  to  cultivation  of  a  particular  kind,  his  interests  may 
not  allow  him  to  enter  upon  it.  The  more  abundant  any 
article  is,  the  lower  will  be  its  price ;  he  ought  then  to 
prefer  those  crops  of  which  the  sale  is  most  secure.  If  a 
product  cannot  be  consumed  upon  the  spot,  it  is  necessary 
to  calculate  the  expense  of  transporting  it  to  a  place  of  sale 
in  countries  where  it  is  needed. 

A  proprietor  ought  to  provide  largely  for  the  wants  of 
his  animals  and  of  the  men  living  upon  his  estate,  before 
arranging  for  the  disposal  of  surplus  crops :  he  will  then 
calculate  his  various  harvests  in  such  a  manner  as  to  be 
always  secure  of  receiving  from  the  earth  the  means  of 
subsistence  for  those  employed  in  performing  the  labor. 

An  intelligent  farmer,  whose  lands  lie  at  a  distance  from 
a  market,  will  endeavour  to  avoid  the  expenses  incident  to 
the  transportation  of  his  products ;  and  in  order  to  do  this, 
he  will  give  the  preference  to  those  harvests  of  fodder  or 
of  roots  which  may  be  consumed  upon  the  place  by  his 
dependants  and  his  animals. 

There  is  another  circumstance  which  must  be  attended 
to  in  sowing  those  lands  which  are  light,  or  which  lie  upon 
a  slope ;  for  these  it  is  necessary  to  employ  such  vegetables 
as  cover  the  soil  with  their  numerous  leaves,  and  unite  it 
in  every  direction  by  their  roots,  thus  preserving  it  from 
being  washed  away  by  rains,  and  at  the  same  time  protect- 
ing it  from  being  too  much  dried  by  the  burning  rays  of 
the  sun. 

In  order  to  support  by  example  the  truth  of  the  princi- 
ples which  I  have  here  laid  down,  I  will  make  a  statement 
of  the  series  of  crops  that  are  found  most  advantageous  in 
those  countries  where  agriculture  is  the  most  flourishing. 
I  shall  commence  with  the  provinces  of  ancient  Flanders, 
because  there  the  art  of  cultivating  the  soil  to  the  greatest 
advantage  had  its  birth. 

In  the  departments  of  Lille  and  Douai,  where  the  soil  is 
of  the  best  kind,  and  the  art  of  preparing  and  employing 
manures  is  carried  to  the  greatest  perfection,  the  following 
series  of  crops  are  adopted. 

First  Series.       F^ax  or  cabbage. 

Wheat. 

Beans. 

Oats,  with  trefoil. 

TrefoU.     . 

Wheat. 


SUCCESSION    OF    CROPS.  139 

Second  Series.     Turnips. 

Oats  or  barley,  with  trefoil. 

Trefoil.  • 

Wheat. 
Third  Series.     Potatoes. 

Wheat. 

Roots,  such  as  turnips  or  beets. 

Wheat. 

Buckwheat. 

Beans. 

Oats  and  trefoil. 

Trefoil. 

Wheat. 
In  this  rotation  of  crops  we  find  that  after  the  soil  has 
been  manured,  the  crops  that  are  most  exhausting  are  re- 
placed by  those  that  are  less  so ;  and  those  that  foul  the 
soil,  by  those  that  cleanse  it  by  requiring  frequent  weed- 
ings. 

It  is  by  similar  means  that  nearly  the  whole  sea  coast  of 
Belgium,  consisting  of  sterile  sand,  has  been  rendered  as 
fertile  as  the  best  soil ;  and  the  richest  harvests  have  followed 
from  a  judicious  system  of  cropping. 

Upon  the  sands  in  the  neighbourhood  of  Bruges,  Ostend, 
Nieuport,  Arvens,  &lc.,  the  cultivation  of  the  grains  is  made 
to  alternate  advantageously  with  that  of  beans,  cabbage, 
potatoes,  and  carrots.  The  system  of  cropping  practised  in 
Norfolk,  and  so  much  praised  by  the  English,  consists  in 
commencing  the  series  by  the  cultivation  of  roots  in  a  well 
manured  soil;  these  are  followed  by  oats  or  barley  with 
trefoil,  and  afterwards  by  wheat. 

In  the  bed  of  dry  sand  which  forms  the  soil  of  Cam- 
pine,  the  industrious  inhabitants  have  with  equal  success 
vanquished  all  obstacles,  and  fertilized  the  soil.  It  is  sur- 
prising to  find  in  these  plains  of  sand,  excellent  crops, 
which,  by  their  judicious  arrangement,  are  constantly  ame- 
liorating the  soil.  The  series  which  is  there  followed  is 
this. 

Potatoes. 

Oats  and  trefoil. 

Trefoil. 

Rye. 

Turnips 
During  a  tour  which  I  made  with  Napoleon  in  Belgium, 
I  heard  him  express  to  one  of  the  ocuncrl  of  a  department. 


ISO  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

his  surprise  at  the  vast  extent  of  waste  land  over  which  he 
had  just  travelled:  he  was  answered  thus;  "Give  us  a 
canal  to  transport  our  manures,  and  to  convey  away  our 
produce,  and  in  five  years  this  sterile  country  will  be  covered 
with  crops."  The  canal  was  afterwards  constructed,  and 
the  promise  realized  in  less  than  the  required  time. 

In  the  interior  of  France,  where  cattle  subsist  almost 
entirely  upon  fodder,  and  are  not,  as  in  the  northern  coun- 
tries, fed  upon  the  mash  from  breweries  and  distilleries, 
crops  of  the  various  plants  used  for  their  support  should  be 
more  extensively  cultivated,  and  should  occur  more  fre- 
quently in  the  rotations. 

In  all  the  compact  and  slightly  argillaceous  soils  upon 
my  estates,  if  they  are  deep,  after  having  had  them  well 
-dressed  with  barn-yard  manure,  I  commence  my  series  of 
crops  with  beets,  to  which  succeeds  wheat,  which  I  sow 
immediately  after  having  drawn  the  beets,  and  without  any 
intermediate  tilling;  the  wheat  I  replace  by  artificial 
grasses,  and  these  by  oats.  When  the  land  is  of  very  good 
quality,  I  follow  wheat  by  clover,  and  this  in  its  turn  is 
succeeded  by  the  grains,  and  by  roots. 

In  light  soils,  which  are  deep  and  sandy  but  fresh,  such 
as  those  upon  the  borders  of  the  ]L.oire,  which  are  sub- 
merged once  or  twice  every  winter,  I  sow,  first,  winter 
vetches,  which  produce  abundantly,  and  these  I  replace  by 
beets. 

Independently  of  the  use  which  I  have  for  beets  in  my 
sugar  manufactory,  I  believe  this  plant  may  be  cultivated  as 
food  for  cattle,  more  advantageously  than  any  other.  The 
leaves  of  those  that  have  completed  their  growth,  may  be 
used  as  food  for  animals  during  the  months  of  August  and 
September ;  and  the  roots  supply  a  quantity  of  nourishment 
of  from  twenty  to  thirty  thousand  weight  per  acre,  or  more 
than  forty  thousand  per  hectare. 

Lands  of  the  best  kind,  that  is  to  say,  lands  which,  to  a 
good  mixture  and  sufficient  depth,  unite  a  favorable  ex- 
posure and  suitable  manures,  may  receive  into  their  series 
of  crops  all  the  plants  adapted  to  the  climate ;  but  there  are 
not  many  soils  possessing  all  these  qualities. 

In  the  siliceous,  and  calcareous  soils,  as  they  are  gener- 
ally dry,  may  be  alternated  crops  of  rye,  barley,  and  white 
rye,  with  those  of  sainfoin,  lupines,  lentils,  French  beans, 
chick  peas,  radishes,  woad,  buckwheat,  potatoes,  &c. 

Preference  shou'd  always  be  given  to  those  crops  which 


PRODUCTS  OF  FRENCH  AGRICULTURE.        131 

experience  has  declared  to  be  best  suited  to  the  soil  and 
climate,  as  well  as  to  those  of  which  the  products  are  the 
most  advantageous  to  the  proprietor. 

In  compact  lands,  containing  a  portion  of  clay,  and 
which  from  their  quality  are  suitable  for  wheat,  the  succes- 
sive crops  may  consist  of  wheat,  oats,  trefoil,  clover,  vetch- 
es, beans,  turnips,  radishes,  cabbages,  mustard,  &/C.  A 
succession  or  rotation  of  crops  should  be  established  in 
these  various  soils,  according  to  the  principles  which  I 
have  explained. 

A  succession  of  crops  well  conducted,  economizes  labor, 
manure,  expense  of  transportation,  &lc.  :  it  furnishes  the 
means  of  raising  and  fattening  a  greater  number  of  ani- 
mals, and  it  ameliorates  the  soil  to  such  a  degree  as  en- 
tirely to  change  its  nature ;  so  that  the  most  delicate  plants, 
and  those  requiring  the  most  nourishment,  may  be  raised 
in  a  soil  originally  sterile  and  ungrateful.  The  arid  sands 
of  Belgium,  and  many  of  the  alluvions  on  the  borders  of 
our  great  rivers,  offer  numerous  examples  of  the  truth  of 
this.  A  good  system  of  cropping  alone  can  give  security 
of  a  lasting  prosperity  in  agriculture. 


CHAPTER  VIIL 


VIEW   OP   THE    PRODUCTS    OF    FRENCH    AGRICULTURE. 

A  REGISTER  of  the  products  of  French  agriculture,  made 
with  great  care  from  1800  till  1812,  gives  as  the  mean 
result  of  these  twelve  years,* 

1.  Wheat 51,500,200  hectolitres. t 

2.  Rye  and  meslin  {meteil)      .     30,290,161 

3.  Indian  corn 6,302,316 

4.  Buckwheat       8,509,473 

5.  Barley 12,576,503 

6.  Dry  pulse 1,798,616 

*  For  the  details  relative  to  the  various  products  here  united  in  a 
tabular  form,  the  reader  may  consult  my  Treatise  on  French  Indiistry. 
He  will  there  find,  not  only  the  observations  and  the  data  which  were 
deemed  necessary  to  establish  these  results,  but  also  the  valuation  and 
estimate  of  all  these  products  in  money. 

[t  The  hectolitre  is  equivalent  to  22.009667  gallons.  —  Tr.] 


132 


CHYMISTRY    APPLIED       f    A  fRICULTURE. 


7.  Potatoes 

8.  Oats        .     . 

9.  Small  grains 

10.  Wines 
merino 

11.  Wool,^  half-breed 
common 


■•{ 


19,800,741  hectolitres 
32,066,587 

1,103,177 

35,358,890 

790,175 

3,901,881 
33,236,487 


1". 


logram- 
mes.* 


Total         37,928,543  kilogr. 

12.  Cocoons  of  silk     ....       5,157,609  kilogr. 

13.  Hemp  and  flax       ....     49,677,300 

14.  Oils  of  all  kinds  ....  130,000,000 
Independently  of  the  principal  products  of  French  agri- 
culture above  enumerated,  there  are  several  distinct  crops, 
which,  without  presenting  such  large  results,  enrich  cer- 
tain localities:  as,  for  example,  madder,  saffron,  hops, 
woad,  fruits,  green  pulse,  &c. 

I  think  it  proper  to  add  to  the  above  table,  that  of  the 
animals  whicih  are  more  or  less  employed  in  agriculture. 

1.  Oxen 1,701,740 

2.  Bulls       214,131 

3.  Cows 3,909,959 

4.  Heifers         856,122 

5.  Horses  or  mules    .     .     .  1,406,671 

6.  Colts 464,659 

7.  Pure  merino  sheep     .     .  766,310 

8.  Half-breed  merino  sheep  3,578,748 

9.  Common  sheep     .     .       30,845,852 
10.  Swine 3,900,000 


CHAPTER   IX. 

OP  THE  NATURE  AND  USES  OP  THE  PRODUCTS  OF 
VEGETATION. 

*  The  elements  that  enter  into  the  composition  of  plants, 
are  but  few  in  number;  but  the  proportions  in  which  they 
are  combined  establish  so  great  a  difference  in  the  prod- 
ucts   of  vegetation,   that  it  seems  almost  incredible,    that 


r*  The  kilogramme  is  equivalent  to  2.20548  lbs.  avoirdupois.  — Tr.] 


NATURE    AND    USES    OF    PRODUCTS.  133 

these  should  be  the  effect  of  so  small  a  number  of  princi- 
ples, varying  only  in  the  proportions  in  which  they  are 
united. 

The  aliments  of  plants  are  water,  air  and  manures: 
these  substances  absorbed  by  the  leaves,  the  fruits,  or  the 
roots,  furnish  by  analysis,  carbonic  acid,  hydrogen,  a  lit- 
tle azote,  and  some  earthy  and  saline  principles :  it  is 
from  these  materials  that  the  almost  endless  variety  of 
widely  differing  products  of  plants  is  formed  by  their  or- 
gans. 

During  the  progress  of  vegetation  these  products  are 
found  to  undergo  successive  changes;  that  which  is  first 
acid  becomes  sweet ;  that  which  is  tender  becomes  hard, 
and  all  is  owing  wholly  to  the  constant  changes  taking 
place  in  the  proportions  of  the  constituent  principles  ;  and 
one  is  astonished  at  finding  that  the  most  exact  analysis  of 
substances  possessing  the  most  opposite  characteristics, 
detects  no  other  difference  than  some  hundredths  more  or 
less  in  the  proportions  of  their  elements. 

When  a  plant  has  completed  or  terminated  its  various 
stages  of  vegetation,  the  dead  remains,  if  exposed  to  the 
action  of  the  same  agents,  such'  as  air,  water,  and  heat, 
suffer  a  succession  of  retrograde  changes  ;  they  are  grad- 
ually decomposed,  and  their  constituent  principles  enter 
into  combination  with  those  of  the  bodies  by  which  they 
are  acted  upon  ;  thus  the  dead  plant  is  entirely  governed 
by  those  invariable  physical  and  chymical  laws,  which  in 
the  living  plant  are  governed  and  modified  by  the  laws  of 
vitality,  the  action  of  which  regulates  that  of  all  external 
agents,  and  produces  results  which  we  can  neither  explain 
nor  imitate. 

Though  great  caution  should  be  used  when  endeavouring 
to  establish  an  analogy  between  two  modes  of  existence 
differing  so  widely  as  those  of  animals  and  vegetables,  it 
must  be  perceived  that  there  is  a  resemblance  in  the  manner 
in  which  both  are  nourished. 

Animals  inhale  air  by  their  lungs,  or  absorb  it  by  glands 
scattered  over  their  bodies ;  they  are  nourished  by  solid 
aliments  received  into  their  stomachs,  or  into  some  analo- 
gous organ  :  plants  absorb  air  by  their  leaves  and  fruits,  and 
imbibe  through  their  roots  the  nutritive  juices  contained  in 
the  earth.  In  animals,  the  juices  circulate  through  every 
part,  and  pass  into  all  the  various  organs,  in  which  they  are 
elaborated,  in  order  to  form  all  the  products  whiph  belong 
12 


lo4  CHYMISTRY    APPLFED    TO^  AGKICULTCTRE, 

io  this  kingdom :  in  vegetables  the  juices  are  carried  mto 
the  bark^  the  alburnum,  the  pith,  the  wood,  the  leaves 
and  the  fruit,  by  tubes  and  glands,  which  are  arranged  in 
hexagonal  cells,  and  are  very  numerous  in  the  parenchyma ^ 
and  in  the  cortical  layers  of  the  bark  :  the  juices  undergo 
particular  modifications  in  the  various  organs,  and  form  in 
each  one  of  them  new  compounds  differing  from  each 
other. 

The  leaves  receive  the  sap  in  vessels  of  the  most  delicate 
texture ;  in  these  it  is  elaborated,  and  combined  with  sub- 
stances absorbed  from  the  atmosphere,  whilst  the  surplus  of 
water,  as  well  as  the  oxygen  of  the  carbonic  acid  from 
which  they  have  extracted  the  carbon,  is  given  out  by  the 
leaves  through  their  transpiring  pores.  The  sap,  after  exr 
periencing  these  changes,  passes  into  the  organs  of  the 
plant,  where  it  is  subjected  to  new  elaborations. 

The  leaves  are  to  plants  what  the  lungs  are  to  animals  j 
those  receiving  the  sap,  as  these  do  the  blood,  to  be  mingled 
in  them  with  the  gas  absorbed  from  the  atmosphere,  and  to 
pass  thence  into  the  great  vascular  system;  and  from  both 
leaves  and  lungs  the  superfluous  water  and  gases  are  thrown 
out  into  the  air. 

We  likewise  find  a  great  variety  of  structure  amongst 
the  various  species  of  which  the  two  kingdoms  are  com- 
posed ;  some  have  a  soft,  loose,  parenchymatous  formation ; 
others  present  a  harder  and  dryer  tissue ;  this,  in  vegetables, 
is  owing  to  the  predominance  of  carbon  ;  in  animals,  to  that 
of  phosphate  of  lime;  these  two  principles,  though  very 
different,  form  the  basis  of  their  separate  structures.  The 
same  elements  enter  into  the  composition  of  all  the  products, 
whether  animal  or  vegetable ;  the  difference  between  them 
arising  solely  from  the  different  proportions  of  the  constitu- 
ent principles. 

An  analysis  of  the  principal  products  of  vegetation  has 
been  made  with  great  care  by  Messrs.  Gay-Lussac  and 
Thenard.  The  results  of  these  researches  enable  us  already 
to  draw  some  conclusions  in  regard  to  the  character  of  any 
one  of  the  products,  according  as  this  or  that  principle  may 
predominate  in  its  composition ;  or  according  to  the  nature 
of  the  elements  combining  to  form  it.     Thus  we  know, 

1.  That  a  vegetable  substance  is  acid  when   it  contains 
no  azote,  and  when  the  quantity  of  oxygen  in  proportion  to 
that  of  hydrogen,  is  greater  than  is  necessary  for  the  format 
ion  of  water 


GUM    AND    MUCILAGE,  13o 

"2.  That  when  the  proportion  of  hydrogen  to  that  of  ox- 
ygen is  greater  than  is  necessary  for  the  formation  of  water, 
the  substance  is  oily,  resinous,  axoholic,  or  ethereal. 

3.  That  when  the  quantity  of  oxygen  and  hydrogen  con- 
tained in  a  substance  is  the  same  as  in  water,  the  substance 
is  analogous  to  sugar,  gum,  fibre,  &.c. 

I  shall  in  this  work  speak  only  of  such  products  of  vege- 
tables as  are  most  common,  or  of  the  most  extensive  use, 
either  for  domestic  purposes,  or  in  the  arts ;  and  I  shall 
endeavour  as  much  as  possible  to  follow  the  order  prescribed 
by  the  analogy  of  their  constituent  principles. 


ARTICLE  I. 
Gum  and  Mucilage. 

MucFLAGE  appears  to  be  in  the  greater  part  of  vegetables 
the  effect  of  the  first  change  wrought  upon  the  sap  by  the 
laws  of  vitality ;  and  the  gums,  which  differ  so  little  from  it, 
are  generally  formed  upon  trees  by  the  extravasation  of  the 
sap,  during  the  period  of  most  vigorous  vegetation.  This 
first  product  of  vegetation  appears,  however.,  to  be  perma- 
nent through  all  its  stages  :  the  leaves  of  the  marsh  mallows, 
the  seeds  of  flax,  lichens,  and  the  bulbs  of  hyacinths  fur- 
nish it  at  all  times ;  so  that  it  appears  to  be  a  constant  and 
inherent  product  of  their  composition. 

Gum  exists  in  a  liquid  form  in  the  cells  of  plants ;  it 
hardens  by  exposure  to  the  air,  loses  a  portion  of  its  trans- 
parency, experiences  a  greater  or  less  change  of  color,  and 
becomes  slightly  brittle.  Mucilage  preserves  its  consistency 
a  longer  time,  though  it  has  less  affinity  for  water 

Gum  and  mucilage  are  soluble  in  water,  from  which  they 
may  be  precipitated  by  alcohol,  and  by  sulphuric  acid  :  they 
burn  with  difficulty,  and  during  ignition  give  out  but  little 
flame,  and  produce  a  great  deal  of  smoke ;  their  residuum 
consists  of  bubbles  of  carbon. 

The  gums  that  are  most  used  in  the  arts,  are  gum  Ara- 
bic, gum  Senegal,  and  the  reddish  gum  of  the  country, 
which  forms  in  tears  upon  the  branches  and  trunks  of  plum, 
cherry,  apricot,  and  many  other  trees. 

Crum  and  macilage  may  he  employed  as  food.:  mucilage 


136  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

is  sometimes  prescribed  in  medicine  as  a  mild,  soothing, 
and  easily  digested  article  of  nourishment. 

The  use  of  gum  in  the  arts  is  very  extensive :  it  is  used 
in  preparing  cloths  and  felt  for  receiving  a  gloss ;  writing- 
paper  is  covered  with  a  thin  coating  of  it  to  prevent  the 
ink  from  spreading.  Gum  is  used  as  a  receiver  of  the 
colors,  which  are  applied  by  impression  to  cloths  of  all 
kinds :  the  use  of  it  in  stamping  cotton  and  linen  goods  is 
now  superseded  in  England  by  that  of  mucilage  extracted 
from  lichens. 

The  specific  gravity  of  the  gums  is  from  1300  to  1490, 
water  being  1000.  Messrs.  Gay-Lussac  and  Thenard  found 
gum  Arabic  to  contain 

Carbon 42.23 

Oxygen 50.84 

Hydrogen 6.93 

Oxygen  and  hydrogen  are  found  in  it  in  the  proportions 
necessary  for  forming  water. 


ARTICLE  II. 

Starch  or  Fecula. 

Starch  is  a  white,  finely  divided,  pulverulent  .substance, 
insoluble  in  cold  water,  and  forming  a  glue  in  boiling 
water.  When  this  substance  is  obtained  from  any  other 
plant  than  one  of  the  grains,  as  from  potatoes,  corn-flag, 
bryony,  horse-chestnut,  male  orchis,  dog-bane,  burdock, 
iris,  hen-bane,  patience,  ranunculus,  &c.,  it  is  known  by 
the  name  of  fecula. 

In  many  parts  of  America  the  principal  food  of  the 
inhabitants  is  procured  from  the  fecula  of  the  manioc. 
The  preparation  of  sago  from  the  pith  of  old  palm  trees, 
and  of  salep  from  the  bulbs  of  all  the  varieties  of  orchis, 
shows  the  important  purposes  which  may  be  answered  by 
the  fecula  of  various  plants,  in  the  arts,  in  medicine,  and 
as  nourishment  for  the  human  species  and  for  animals. 
The  fecula  contained  in  all  the  plants  I  have  just  named 
is  wholesome,  and  very  nourishing,  and  may  be  used  as 
food  in  various  forms ;  but  it  is  necessary  to  keep  in  mind, 
that  in  most  of  these  vegetables  it  is  combined  with  other 


-STARCH    OR    FECnULA,  137 

substaDces  either  actually  poisonous,  or  possessing  a  sharp, 
bitter,  acrid,  or  otherwise  disagreeable  taste  :  it  is  there- 
fore of  the  greatest  consequence  that  the  fecula  should  be 
prepared  from  them  with  the  utmost  attention  to  freeing 
it  from  every  other  portion  of  the  plant.  Fortunately  the 
nature  of  the  substances  which  are  united  with  tlie  fecula 
is  so  different  from  that  of  the  fecula  itself,  and  the  char- 
acteristics of  each  are  so  distinct,  and  so  well  marked, 
that  they  can  be  separated  from  each  other  by  a  process 
equally  easy  and  sure.  The  great  solubility  in  water  of 
all  the  injurious  principles,  and  their  extreme  levity  when 
compared  with  the  weight  of  the  fecula,  causes  them,  when 
exposed  to  repeated  washings,  to  rise  to  the  top  of  the 
vessel  in  which  the  operation  is  performed,  whilst  the 
fecula,  freed  from  any  mixture,  remains  at  the  bottom. 

Two  processes  are  employed  for  extracting  fecula ;  both 
must  be  commenced  by  reducing  to  a  state  of  fine  division 
the  substance  containing  it  The  fecula  is  afterwards 
obtained  either  by  means  of  cold  water  alone,  or  by  fer- 
mentation. The  first  of  these  methods  is  the  most  simple 
and  expeditious,  but  by  it  all  the  fecula  is  not  obtained; 
the  second,  therefore,  though  longer  and  more  expensive 
is  preferred  for  extracting  starch  from  the  grains. 

When  starch  is  to  be  extracted  by  cold  water,  the  sub- 
stance must  either  be  reduced  to  the  state  of  flour,  or  be 
broken  so  that  the  pulp  can  be  acted  upon  by  the  water. 

In  the  first  case,  the  flour  of  wheat  is  kneaded  with 
water,  till  it  takes  the  consistency  of  a  stiff*  paste ;  this  is 
placed  on  a  cloth  stretched  tightly  over  a  tub,  and  cold 
water  thrown  upon  it ;  the  kneading  with  the  hand  is 
continued  till  the  water  runs  off"  clear ;  the  fecula  is  car- 
ried off"  by  the  water  and  deposited  at  the  bottom  of  the 
tub ;  the  water  retains  in  solution  the  sugar  and  the  ex- 
tractive matter  of  the  farina,  whilst  the  insoluble  gluten 
alone  remains  uf>on  the  filter ;  the  deposit  is  washed  to 
free  it  from  any  foreign  substance,  and  then  dried.  When 
it  is  not  wished  that  the  substance  containing  the  fecula 
should  be  reduced  to  flour,  it  may  be  broken  in  a  mortar, 
or  under  a  mill-stone,  or  it  may  be  grated ;  the  pulp  is  then 
to  be  placed  upon  a  very  fine  horse-hair  sieve,  and  water 
thrown  upon  it  till  it  runs  off  clear;  care  being  taken  to 
stir  the  pulp  constantly  with  the  hand  and  to  squeeze  it 
hard. 

When  the  substance  from  which  the  fecula  is  to  be  e/- 
12* 


138  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

tracted  is  fleshy,  and  of  a  loose,  spongy  texture,  it  can  be 
reduced  to  a  pulp  by  means  of  a  press;  the  juice  thus 
expressed  deposits  the  fecula,  which  must  be  very  carefully 
washed,  in  order  that  the  noxious  principles  contained  in 
it  may  be  perfectly  separated.  The  whiteness  and  ex- 
cellence of  the  fecula  depends  upon  its  being  thoroughly 
washed. 

Fermentation  is  the  means  most  commonly  employed 
for  extracting  starch  from  grain ;  but  this  operation  will 
produce  only  alcohol,  if  care  be  not  taken  in  mixing  the 
acid  with  the  grain,  to  prevent  the  spirituous  fermentation. 
This  acid  is  made  by  mixing  with  a  bucket  of  hot  water 
two  pounds  of  baker's  yeast,  to  which  is  added,  two  days 
after,  several  buckets  of  hot  water ;  in  forty-eight  hours 
from  that  time  the  acid  will  be  sufficiently  developed. 

This  acid,  which  is  called  by  the  starch  manufacturers 
sure  ivater,  contains  nothing  but  vinegar,  and  I  therefore 
presume,  that  the  acetic  acid  may  be  used  with  the  same 
success. 

In  order  to  extract  the  starch  by  fermentation,  a  bucket 
of  this  sure  water  is  thrown  into  a  hogshead  having  one 
end  taken  out.  The  hogshead  is  then  filled  half  full  of 
common  water,  into  which  flour  is  stirred  till  it  is  full ; 
the  whole  is  then  left  to  macerate  during  ten  days  in 
summer,  and  fourteen  in  winter.  The  sufficiently  ad- 
vanced state  of  the  maceration  may  be  known  by  a  de- 
posit being  formed,  and  the  liquor  swimming  above  it  re- 
maining clear,  whilst  the  surface  is  covered  with  foam  or 
fat  water.  The  water  and  foam  is  drawn  off*,  and  the 
deposit  is  thrown  into  a  sack  of  hair-cloth,  which  is  placed 
in  a  tub,  and  water  thrown  over  it  till  it  runs  off"  without 
any  cloudiness.  The  substance  remaining  in  the  bag, 
which  is  only  the  coarsest  part,  serves  as  food  for  cattle. 
At  the  end  of  two  or  three  days,  the  water  floating  above 
the  deposit  formed  in  the  tub  is  drawn  off*,  and  a  part  of  it 
preserved  to  serve  as  sure  water,  for  succeeding  operations. 

In  order  to  have  good  starch,  the  deposit  must  be  wash- 
ed in  a  great  deal  of  water  and  well  mixed ;  two  or  three 
days  after,  the  water  for  the  remaining  washings  may  be 
thrown  on. 

The  deposit  which  is  formed  presents  three  layers  diff*er- 
ing  widely  in  their  quality ;  the  first  is  principally  com- 
posed of  fragments,  and  is  taken  off*  as  food  for  cattle,  or 
to  fatten  hogs  with.     The  second  layer  is  generally  formed 


STARCH  OR  PECULA.  1^ 

of  the  mealy  part  of  the  vegetable  mixed  with  some  other 
substances:  the  product  of  this  layer  is  known  under  the 
name  of  common  starch. 

The  third  layer  contains  the  purest  and  heaviest  starch ; 
but  in  order  to  give  it  all  the  qualities  it  ought  to  possess, 
it  must  be  washed  with  water,  and  the  water  afterwards  sep- 
arated from  it  by  filtration  through  a  sieve  of  silk,  so  as  to 
free  it  from  all  impurities.  With  these  precautions  starch 
may  be  obtained  fitted  for  any  use. 

As  soon  as  the  starch  has  been  well  washed,  it  is  put  into 
baskets  lined  with  linen,  to  be  well  drained.  It  is  afterwards 
divided  into  loaves,  and  the  drying  finished  by  exposing  it 
in  the  open  air  upon  laths.  Before  packing  for  sale,  the  sur- 
face of  the  loaves,  which  is  slightly  colored,  is  scraped,  and 
the  drying  of  them  is  completed  in  the  sun  or  in  a  stove. 

The  use  of  starch  and  of  fecula  is  very  extensive ;  starch 
mixed  with  boiling  water,  takes  the  consistency  of  jelly,  and 
forms  size ;  when  tinged  with  blue,  it  is  used  for  giving  a 
gloss  and  stiffness  to  linen ;  when  reduced  to  a  fine  powder, 
it  is  used  for  dressing  the  hair.  Fecula  forms  the  basis  of 
the  greater  part  of  our  food,  and  is  in  itself  an  excellent 
article  of  nourishment. 

Starch  acted  upon  by  sulphuric  acid  is  converted  into 
sugar,  and  in  this  state  may  be  made  to  undergo  the  vinous 
fermentation.  A  few  years  since  extensive  establishments 
were  formed  in  France,  for  supplying  numerous  distilleries 
with  the  fecula  of  the  potato,  which  had  been  treated  in 
this  manner. 

Starch  thrown  upon  red-hot  iron,  burns,  leaving  scarcely 
•ny  residuum. 

Messrs.  Gay-Lussac  and  Thenard  have  found  that  100 
parts  of  starch  contain 

Carbon 43.55 

Oxygen 49.68 

Hydrogen 6.77 

So  that  in  starch,  as  in  gum  and  mucilage,  oxygen  and 
hydrogen  are  combined  in  the  same  proportions  as  in  water; 
and  those  substances  resemble  starch  in  their  characteristics, 
and  in  their  uses. 


140  CHYMISTRY    APPLIED   TO   AGRICULTURE. 

ARTICLE   III.. 

Sugar. 

Sugar  is  a  substance'  of  a  sweet  and  agreeable  taste 
which  is  extracted  from  certain  vegetables :  it  is  light 
colored,  and  when  dissolved  in  water  to  which  a  little 
yeast  has  been  added,  is  capable  of  undergoing  the  vinous 
fermentation.  All  those  substances  that  experience  the 
same  fermentation  by  the  same  means,  contain  more  or 
less  sugar.  The  same  characteristic  may  be  bestowed  by 
art  upon  many  other  products  of  vegetation,  causing  them 
to  vary,  by  chymical  processes,  the  proportions  of  their 
constituents,  till  they  approach  those  of  sugar;  it  is  in 
this  way  that  starch  and  vegetable  fibre  may  be  made  to 
undergo  the  vinous  fermentation.  All  those  substances 
that  possess  the  property  of  forming  the  vinous  fermentation, 
may  be  called  by  the  general  name  of  sugar.  There  are 
three  kinds  of  sugar,  the  characteristics  of  which  are  very 
distinct ;  the  first  and  most  important  is  that  which  crystal- 
lizes, and  to  which  the  generic  name  of  sugar  is  given ; 
this  is  furnished  by  the  sugar  cane,  the  beet,  carrot,  turnip, 
chestnut,  maple,  &c. 

The  sugars  procured  from  these  different  plants,  are, 
strictly  speaking,  of  the  same  nature,  and  do  not,  when 
brought  by  the  process  of  refining  to  the  same  degree  of 
purity,  differ  in  any  way  from  each  other :  their  taste,  man- 
ner of  crystallization,  color,  and  weight  are  then  precisely 
the  same,  and  no  person,  however  much  in  the  habit  of 
judging  of  these  products,  or  of  consuming  them,  can  dis- 
tinguish one  from  the  other. 

The  second  kind  of  sugar,  is  that  which  is  extracted 
from  the  must  of  grapes ;  this  always  appears  in  the  form 
of  a  white  powder,  in  which  no  trace  of  crystallization  can 
be  found ;  it  possesses  the  properties  of  the  first  kind  of 
sugar,  and  provided  a  double  portion  of  it  be  used,  an- 
swers the  same  purposes.  During  the  time  when  American 
sugar  was  scarce,  and  consequently  excessively  dear  in 
France,  an  enormous  quantity  of  grape  sugar  was  manufac- 
tured and  sold  at  a  low  price. 

The  third  kind  of  sugar,  is  that  which  is  contained  in 
nearly  all  fruits ;  this  not  only  refuses  to  crystallize,  but 
cannot  be  made  to  assume       solid  form.    The  juices  cf 


WAX.  141 

these  fruits  may  be  reduced  to  a  sirup  supplying  for  many 
purposes  the  j^ace  of-6ugar,  and  of  great  use  as  an  article 
of  food.  By  concentrating  these  nutritive  substances,  the 
advantage  of  reducing  them  to  a  small  bulk  is  added  to 
that  of  preserving  them  from  decomposition:  the  same 
effects  are  produced  by  concentrating  them  to  a  jelly  or 
an  extract.  Those  sweet  juices,  that  are  not  convertible 
into  sirups,  will,  by  being  fermented,  form  a  vinous  liquor, 
equally  useful,  healthful,  and  agreeable,  to  a  great  portion 
of  the  people. 

Those  substances,  which  are,  by  the  aid  of  chymistry, 
convertible  into  sugar,  furnish  only  the  second  kind  of  it ; 
this  is  very  suitable  for  being  made  by  fermentation  to 
produce  alcohol. 

The  specific  gravity  of  sugar  is,  according  to  Fahren- 
heit, 1.6 ;  it  dissolves  in  its  own  weight  of  water,  at  the 
temperature  of  50°.  Sugar  contains  42.47  per  cent,  of 
carbon ;  hydrogen  and  oxygen  are  found  in  it  as  in  the 
gums,  in  the  same  proportions  as  in  water. 


ARTICLE   IV. 
Wax. 

Though  wax  can  be  extracted  in  considerable  quanti- 
ties only  from  the  berries  of  the  myrica  cerifera^  yet  it  is 
contained  in  nearly  all  p'ants ;  it  exists  in  greater  or  less 
quantities  in  the  leaves  o  most  trees.  Wax  is  also  formed 
by  the  decomposition  ot  several  roots;  for  if,  when  the 
first  operations  are  performed  for  extracting  sugar  from 
the  juice  of  beets,  they  be  not  well  conducted,  from  the 
moment  the  boiling  of  tne  concentrated  sirup,  in  order  to 
form  the  sugar,  is  commenced,  there  collects  upon  the 
surface  a  thick,  whitish,  glutinous  substance,  which,  when 
removed  with  the  skimmer  and  dried,  exhibits  all  the 
characteristics  of  wax ;  it  is  insoluble  either  in  water  or 
alcohol ;  it  burns  like  wax,  and  has  the  same  consistency ; 
nor  does  it  in  any  other  respect  differ  from  it.  It  is  this 
substance  that  adheres  to  the  sides  of  the  boilers  when 
the  sirups  have  become  thickened  by  boiilu^,  beyond  35° 
of  the  aerometer  of  Baurae.     The  burning  of  the  liquor, 


142  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

which  prevents  the  ebullition  from  being  carried  to  a 
sufficient  extent  to  produce  a  good  crystallization  of  the 
sugar,  is  caused  by  this  substance.  There  cannot  be  too 
much  care  taken  in  the  first  operations  to  prevent  this 
deterioration  of  the  sirup,  as  this  alone  has  occasioned 
the  failure  of  most  of  the  establishments,  which  were 
formed  in  France  in  1810,  for  manufacturing  sugar  from 
beets. 

Nearly  all  the  wax  which  is  used  in  the  arts,  and  for 
domestic  purposes,  is  produced  by  bees,  the  cells  of  their 
hives  being  formed  by  it.  This  wax  is  found  in  scales  or 
plates  under  the  abdomen  of  the  insect,  and  appears  to  be 
a  transudation,  which  becomes  thickened,  and  which  the 
bee  detaches  by  rubbing,  to  form  his  cells. 

Wax  is  bleached  by  pouring  it  when  melted  upon  a 
cylinder  partly  immersed  in  water,  and  to  which  a  rapid 
rotatory  motion  is  given.  The  wax,  as  it  flows  over  the 
moistened  surface  of  the  cylinder,  congeals  in  very  thin 
layers,  which  are  afterwards  exposed  upon  cloths  in  the 
sun  for  some  time,  that  they  may  acquire  a  clear  white- 
ness. 

It  does  not  appear,  that  in  the  elaboration  of  wax,  the 
bee  bestows  upon  it  any  animal  character  whatever ;  the 
wax  which  is  furnished  by  bees  is  precisely  of  the  same 
nature  as  that  procured  directly  from  some  vegetables. 
Wasps  build  cells,  which  they  use  for  the  same  purposes 
as  the  bees  do  theirs ;  but  the  materials  of  which  they  are 
constructed  is  ligneous,  and  consists  of  minute  portions  of 
the  fibrous  part  of  vegetables  cemented  by  an  animal  glutt.i. 
According  to  the  analysis  of  Messrs.  Gay-Lussac  and  The- 
nard,  100  parts  of  wax  are  composed  of 

Carbon       81.784 

Oxygen 5.544 

Hydrogen 12.672 

The  property  possessed  by  wax,  of  burning  without  pro- 
ducing either  odor  or  smoke,  has  caused  it  to  be  generally 
used  for  lighting  the  apartments  of  the  wealthy  :  tallow 
and  the  common  oils  have  always  been  used  by  the  poor, 
and  they  are  so  even  at  this  day,  when  science  and  chymis- 
try  have  united  to  perfect  the  mode  of  lighting  by  oil. 


OILS.  143 

ARTICLE  V. 

Oils* 

The  oils  are  fat,  unctuous  bodies,  of  various  degrees  of 
fluidity,  insoluble  in  water,  forming  soap  with  the  alka- 
lies, and  burning  and  evaporating  at  different  tempera- 
tures. It  is  the  last  characteristic,  particularly,  which  es- 
tablishes that  difference  amongst  them  by  which  they  are 
divided  into  fixed  and  volatile  oils.  The  fixed  oils  are 
contained  in  seeds  and  fruits,  from  which  they  are  ex- 
tracted by  pressure.  The  first  portion  which  is  expressed 
is  the  purest,  and  is  known  by  the  name  of  virgin  oil ; 
that  which  follows  is  rendered  more  or  less  impure  by  the 
mixture  of  other  principles  contained  in  the  fruit  submit- 
ted to  compression.  It  is  particularly  by  the  mucilage, 
which  is  found  in  a  greater  or  less  quantity  in  all  vegetables, 
that  the  purity  of  oil  is  affected. 

After  all  the  oil,  which  can  be  extracted  by  pressure, 
has  been  drawn  off,  it  is  customary  to  moisten  the  mash 
with  boiling  water,  and  to  subject  it  to  another  and  more 
powerful  pressure;    but  the  oil  thus  obtained  carries  with 

*  I  make  use  of  the  generic  term  oil,  by  which  two  substances, 
diifering  widely  from  each  other,  have  been  for  a  long  time  known ; 
but  I  ought  to  observe,  that  the  properties  which  are  common  to 
them,  are  not  sufficient  to  authorize  their  being  included  under  one 
name,  and  that  in  all  their  relations  they  present  30  great  a  difference 
as  to  entitle  them  to  be  considered  as  two  kinds  of  products,  and  to  be 
designated  by  specific  names. 

1 .  The  fixed  oils  are  insoluble  in  alcohol ;  the  volatile  oils  are 
soluble. 

2.  The  fixed  oils  have  generally  neither  odor  nor  flavor ;  the  vola- 
tile oils  are  pungent,  caustic,  and  very  odoriferous. 

3.  The  property  of  burning,  common  to  the  two  oils,  belongs  like- 
wise to  all  vegetable  substances  properly  so  called. 

4.  The  fixed  oils  are  obtained  only  from  seeds  and  fruits ;  many 
volatile  oils  are  extracted  from  all  parts  of  plants. 

5.  The  fixed  oils  are  for  the  most  part  employed  as  food  ;  the  vola- 
tile oils  are  useful  only  in  the  arts. 

6.  The  fixed  oils  evaporate  only  at  a  high  degree  of  temperature  ; 
the  volatile  oils  are  dissipated  entirely  at  the  temperature  of  the 
atmosphere. 

7.  The  characteristic  of  forming  soap  does  not  belong  exclusively 
to  the  oils;  it  is  possessed  by  many  other  substances,  animal  ana 
vegetable. 

Thus  wfiat  are  called  volatile  oils  are  only  liquid  or  concrete 
aromas,  and  it  is  in  the  class  of  aromas  that  they  ought  to  be  ranked. 


144  CHYMISTRY   APPLIED    TO    AGRICULTURE. 

it  a  large  portion  of  mucilage,  and  is  usually  employed  only 
in  some  of  the  trades.  In  some  countries  it  is  customary 
to  collect  the  fruits  into  heaps,  and  to  subject  them  to  a 
degree  of  fermentation  before  pressure;  by  this  means  the 
extraction  of  the  oil  is  rendered  easier,  and  the  quantity  of  it 
is  increased,  but  the  quality  of  it  is  much  injured.  Similar 
results  are  obtained  by  breaking  the  fruit  previous  to  ex- 
pressing the  oil. 

It  would  be  hardly  right  to  condemn  these  last  methods 
as  erroneous,  because  in  the  numerous  soap-works,  dye- 
houses,  cloth  manufactories,  &:-c.,  this  quality  of  oil  is 
preferred  to  that  which  is  purer.  The  learned  will  do 
well  to  condemn  the  processes  now  employed  for  procur- 
ing the  fine  oils,  and  to  prescribe  others  by  which  we  may 
obtain  them  purer  and  of  a  better  taste;  but  the  grand 
consumption  of  the  oils  is  in  the  manufactories,  and  there 
the  fine  oils  would  very  imperfectly  replace  those  of  a 
coarser  kind ;  thus,  by  perfecting  the  produce,  the  useful- 
ness of  it  would  be  lessened.  When  oil  is  to  be  extracted 
for  domestic  purposes,  it  is  without  doubt  desirable  that  it 
be  obtained  as  pure  as  possible;  but  that  which  is  destined 
to  be  employed  in  the  trades,  and  in  manufactures,  as  in 
that  of  soap  for  instance,  is  the  better  for  being  combined 
with  a  portion  of  mucilage.  The  great  art  of  manufactur- 
ing consists  in  appropriating  the  products  to  the  wants  and 
tastes  of  consumers. 

When  mucilage  is  so  abundant  in  an  oily  seed,  that  it 
yields  upon  expression  only  a  pasty  combination  of  muci- 
lage and  oil,  the  seed  is  dried  by  fire :  when  the  mucilage 
is  thus  deprived  of  fluidity,  the  oil  flows  off  pure.  In  this 
manner  the  seeds  of  flax,  of  poppies,  of  hen-bane,  &:-c.  are 
prepared  for  expression. 

Nearly  all  oils  are  colored,  and  contain  some  of  the 
principles  of  the  fruits  from  which  they  are  procured ;  these 
are  in  some  of  their  effects  injurious  to  the  oil,  and  great 
pains  has  been  taken  to  find  some  means  of  freeing  it  from 
them.  Oil  is  clarified  to  a  certain  degree  merely  by  stand- 
ing in  a  cool  place  in  open  earthen  vessels;  it  forms  a 
deposit  and  is  thus  rendered  purer,  clearer,  and  better.  If 
oil  is  exposed  to  the  sun  it  gradually  loses  its  color. 

In  order  to  clarify  the  oil  of  mustard,  one  per  cent,  of 
sulphuric  acid  is  put  into  a  large  earthen  pan,  into  which 
the  oil  is  thrown  and  carefully  stirred:  the  oil  becomes 
green,  and  upon  being  allowed  to  remain  at  rest,  forms 


OILS.  145 

upon  the  sides  and  bottom  of  the  pan  a  blackish  deposit, 
which  is  principally  composed  of  carbon  :  the  process 
must  be  repeated  after  a  few  days,  if  the  oil  have  not  ac- 
quired the  wished  for  clearness.  Before  using  the  oil,  it  is 
necessary  that  it  should  be  allowed  to  remain  for  some 
time  undisturbed.  In  this  operation  the  mucilage  appears 
to  be  precipitated  and  consumed  by  the  acid.  Most  fixed 
oils  contain  some  mucilage,  and  most  of  them  become 
rancid. 

Most  fixed  oils  have  but  in  a  very  slight  degree  the 
property  of  drying ;  but  some  of  them  acquire  it  by  being 
combined  with  some  metallic  oxide,  and  this  greatly  in- 
creases the  use  of  them,  as  they  can  in  this  way  be  em- 
ployed as  varnishes  for  covering  bodies  which  it  is  neces- 
sary to  preserve  from  air  and  water  ;  or  as  the  recipients 
of  colors  to  be  used  in  painting  upon  cloth,  wood,  or  metal. 
The  best  drying  oils  are  those  of  flaxseed,  nuts,  and  poppies. 
Linseed  oil  will  dissolve  at  boiling  temperature  ^  of  its 
weight  of  that  oxide  of  lead  known  in  commerce  by  the 
name  of  litharge.  It  becomes  brown  in  proportion  as  the 
oxide  is  dissolved  :  when  saturated  with  the  oxide  it  thick- 
ens by  cooling,  and  it  is  necessary  to  render  it  liquid  by 
heat  at  the  time  of  using  it.  Linseed  oil,  saturated  with  the 
oxide  and  applied  with  a  brush  to  any  substance,  hardens 
readily  and  forms  a  coating  impervious  by  water,  and 
much  resembling  gum  elastic ;  linen  or  silk  prepared  with 
it  is  flexible  without  being  adhesive. 

A  cement  of  this  oil  prepared  with  the  oxide,  and  mixed 
with  the  refuse  or  broken  fragments  of  porcelain  or  of  well 
baked  potter's  ware,  is  used  with  great  success  in  uniting 
the  tiles  upon  roofs,  and  in  cisterns,  and  reservoirs.  To 
form  this  cement  the  pulverized  fragments  are  thoroughly 
incorporated  with  the  heated  oil,  and  applied  by  the  trowel 
whilst  in  that  state. 

When  linseed  oil  is  to  be  used  in  painting,  ^V  or  at  the 
most  ^  part  of  litharge  is  sufficient  to  render  it  drying. 

In  consequence  of  the  numerous  purposes  to  which  the 
fixed  oils  are  applied,  the  consumption  of  them  is  im- 
mense :  they  form  the  basis  of  the  soaps,  both'  soft  and 
hard,  according  as  they  are  combined  with  potash  or  soda  : 
they  are  used  to  fix  in  the  most  durable  manner  upon  cot- 
ton the  colors  obtained  from  madder  :  they  are  employed 
to  facilitate  the  operations  in  all  establishments  for  card- 
ing and  spinning  wool.  It  is  by  the  use  of  oil  that  the  play 
13 


146  CHYMISTRY   APPLIED    TO    AGRICULTITKE. 

of  all  machinery  is  rendered  more  regular  and  easy^  and 
that  friction  is  moderated ;  and  by  it  metals  are  pre- 
served from  rusting. 

The  most  important  use  to  which  oil  has  been  applied  is 
that  of  lighting  buildings ;  but  as  it  gives  out,  in  burning, 
more  or  less  smoke,  and  a  light  inferior  in  brilliancy  to 
that  of  wax,  the  latter  was  preferred  until  the  invention  of 
Argand's  lamps  :  in  these  a  current  of  air  passes  rapidly 
through  a  circular  wick  surmounted  by  a  cylindrical  glass, 
and  thus  the  smoke  is  consumed  and  the  light  rendered 
more  clear  and  brilliant. 

The  products  of  the  combustion  of  the  fixed  oils  are 
water  and  carbonic  acid ;  this  declares  their  constituent 
principles  to  be  carbon,  oxygen,  and  hydrogen.  Messrs. 
Gay-Lussac  and  Thenard  have  found  them  in  the  follow- 
ing proportions. 

Carbon 77.213 

Oxygen 9.427      . 

Hydrogen        15.360 

The  volatile  or  essential  oils  are  more  easily  volatilized 
than  the  fixed  oils ;  they  are  inflammable  at  a  lower  tem- 
perature, are  soluble  in  alcohol,  exhale  a  powerful  odor  by, 
which  they  are  distinguishable  from  each  other,  and  have 
a  lively,  acrid,  and  burning  taste. 

The  volatile  oils  do  not  belong  exclusively  to  any  one 
part  of  plants :  in  some,  as  in  the  Bohemian  Angelica,  the 
oil  is  distributed  throughout  the  whole  plant :  sometimes,, 
as  in  balm,  mint,  and  wormwood,  it  is  found  in  the  leaves 
and  stalks:  the  elecampane,  Florence  iris,  and  bennet 
contain  it  in  their  roots ;  thyme  and  rosemary  in  their 
leaves  and  flower  buds;  lavender  and  the  rose  in  their 
calyces ;  camomile,  lemon,  and  orange  plants,  in  their 
flowers ;  the  petals,  and  the  rind  of  the  fruit  of  the  two 
last  abound  in  oil ;  that  of  indigo  and  fennel  is  contained 
in  vessels  forming  the  raised  lines  which  may  be  perceived 
on  the  bark. 

Volatile  oils  vary  in  color,  consistency,  and  weight: 
there  are  some,  as  that  of  sassafras,  and  the  clove,  for  in- 
stance, which  are  heavier  than  water  ;  and  there  are  some, 
as  those  of  the  rose  and  parsley,  that  remain  in  a  concrete 
state  at  the  usual  temperature  of  the  air,  &c. 

The  volatile  oils  are  extracted  either  by  distillation  or 
expression.  When  the  oil  is  contained  in  vesicles  upon 
the  surface  of  the  rind,  as  is  that  of  the  lemon  and  berga- 


RE«IN.  147 

mot,  the  cells  may  be  broken  and  the  oil  caused  to  flow 
out  by  merely  rubbing  the  rinds  together ;  or,  the  rinds 
may  be  taken  off  by  grating,  and  the  oil  separated  from  the 
pulp  by  a  light  pressure,  or  by  allowing  the  whole  to  remain 
undisturbed  for  a  few  days,  when  the  pulp  will  settle  at  the 
bottom,  and  the  oil  remain  floating  above  it. 

When  these  rinds  are  scraped  with  a  bit  of  sugar,  the  oil 
combines  with  it,  forming  an  oleosaccharum ^  useful  in  giving 
a  pleasant  flavor  to  liquors. 

With  the  exception  of  the  oils  of  which  I  have  just 
spoken,  all  the  volatile  oils  are  extracted  by  distillation : 
in  this  process  the  plant  is  put  into  the  boiler  of  the  alembic, 
and  covered  with  water ;  w  hen  the  water  boils  the  oil  rises 
with  the  steam,  and  is  condensed  with  that  in  the 
worm  of  the  still,  whence  they  flow  together  into  the 
receiver  :  the  oil  which  swims  upon  the  top  is  separated 
from  the  water,  and  this  water,  which  has  a  milky  appear- 
ance, is  again  employed  from  preference  in  new  distilla- 
tions. 

It  is  customary  to  make  use  of  a  narrow,  straight-necked 
Tessel  as  a  receiver :  the  oil  collects  in  the  upper  part  ot 
this,  whilst  the  water  passes  off  through  a  siphon  in  the 
fiide,  about  four  iaches  below  the  neck. 

In  the  south  of  Europe,  where  great  quantities  of  the 
volatile  oils  are  prepared,  the  distillers  place  their  portable 
apparatus  in  the  open  air,  in  those  places  which  offer  a  plen- 
tiful harvest  of  aromatic  plants",  when  these  are  exhausted 
they  remove  elsewhere. 

The  aromatic  oils  are  employed  particularly  as  perfumes, 
and  for  this  purpose  are  often  combined  with  other  eub- 
titances.  They  are  likewise  used  in  the  manufacture  of 
varnishes,  from  the  readiness  with  which  they  dissolve 
colors,  and  from  their  quick  evaporation  after  being  ap- 
plied.- 


ARTICLE  VL 

Resin. 

The  occurrence  of  resin  is  very  common  throughout  the 
whole  vegetable  kingdom,  but  it  is  from  those  trees  which 


148  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

are  most  numerous,  as  pines,  cedars,  &-c.  that  it  is  princi- 
pally extracted,  and  the  term  resinous  is  applied  to  them 
from  the  very  great  proportion  of  resin  contained  in  their 
sap. 

The  mode  of  collecting  resin  is  by  cutting  notches 
through  the  bark  of  the  trunks  of  resinous  trees  near  the 
base,  at  that  season  when  the  sap,  softened  by  the  return- 
ing warmth  of  spring,  begins  to  rise  in  the  vessels.  As 
resin  abounds  principally  in  the  alburnum,  the  notches 
must  be  of  sufficient  depth  to  pass  through  that ;  the  in- 
cisions must  be  enlarged  or  renewed,  once  in  fifteen  days. 
The  flow  of  the  resin  ceases  as  the  return  of  frost  causes 
the  vessels  of  the  trees  to  contract.  A  healthy  and  well- 
grown  tree  will  furnish  from  twelve  to  fifteen  lbs.  of  resin 
per  annum. 

A  different  process  is  made  use  of  in  extracting  resin 
from  dead  trees;  the  bark  and  young  branches  of  these 
are  taken  off,  and  the  remainder  reduced  to  small  pieces 
which  are  piled  up  in  a  heap  and  covered  over,  excepting  a 
small  opening  which  is  left  at  the  top :  the  heat  of  the  fire 
which  is  kindled  at  the  upper  part  is  sufficient  to  melt  the 
resin  which  flows  down  to  the  bottom,  and  is  carried  off  by 
channels,  into  vessels  prepared  to  receive  it. 

This  resin  is  black,  and  contains  a  great  quantity  of 
pyroligneous  acid  and  volatile  oil :  it  is  known  in  commerce 
under  the  name  of  tar;*  the  quality  of  it  varies  according 
to  the  care  with  which  it  is  extracted  :  if  the  heat  be  too 
great,  the  volatile  oil  is  thrown  off,  and  the  resin  rendered 
dry  and  brittle:  it  cracks  when  used,  and  renders  the 
substances  to  which  it  is  applied  less  ductile  and  pliable. 

The  tar  of  southern  climates  has  both  faults  ;  and  it  was 
formerly  necessary  that  the  marine  arsenals  should  be  sup- 
plied with  that  made  in  the  north  of  Europe  ;  but  now  that 
tar  is  manufactured  in  furnaces,  according  to  the  process  of 
M.  Darracq,  in  such  a  manner  as  to  condense  all  the  vola- 
tile oil,  and  thereby  render  the  tar  more  fat,  unctuous,  and 
suitable  for  all  purposes,  it  is  employed  for  naval  purposes, 
equally  with  the  best  tar  of  the  north. 

The  resins  are  insoluble  in  water,  but  very  soluble  in 
alcohol :  they  liquefy  at  a  low  temperature,  and  burn  easi- 

*  A  description  of  the  processes  employed  for  extracting  resins  and 
forming  all  the  resinous  preparations  known  in  commerce,  may  be 
found  in  my  Chirnie  appliqu6e  auz  Arts.    Vol.  II.  page  425-445. 


VEGETABLE    FIBRE.  149 

ly,  giving  out  much  smoke  during  combustion.  Amongst 
our  mountains  the  peasants  have  no  other  method  of  light- 
ing their  dark  dwellings,  than  by  burning  the  wood  of 
resinous  trees. 

The  solubility  of  resin  in  alcohol  occasions  it  to  be  used 
as  a  basis  in  the  spirit-of-wine  varnishes  :  the  dissolvent 
evaporates  as  soon  as  the  varnish  is  applied,  and  leaves  a 
coating  of  resin,  which  preserves  the  body  from  the  action 
of  air  or  water,  and  at  the  same  time  gives  to  it  a  bril- 
liancy, smoothness,  and  a  beautiful  color  which  may  be 
varied  at  pleasure. 

The  smoke  of  resin  condensed  and  collected  in  cham- 
bers hung  with  linen  or  paper,  forms  the  lamp-black  which 
is  commonly  employed  in  painting,  stamping,  printing,  and 
the  composition  of  varnish.  According  to  the  experiments 
of  Messrs.  Gay-Lussac  and  Thenard,  100  parts  of  common 
resin  contain 

Carbon 75.944 

Oxygen 13.337 

Hydrogen       10.719 


ARTICLE  VII. 

Vegetable  Fibre, 

Vegetable  fibre  is  the  frame- work  of  all  the  solid  parts 
of  plants  :  it  may  be  separated  from  vegetable  substances 
by  the  repeated  action  of  water  and  alcohol,  aided  by 
heat ;  by  maceration  for  a  length  of  time ;  or  by  distilla- 
tion. By  the  first  method  the  juices  which  are  lodged  in 
the  intervals  of  the  fibres  are  dissolved ;  by  the  second, 
these  juices  are  decomposed  by  fermentation  ;  by  the  third, 
which  is  the  least  perfect,  those  principles  which  can  be 
volatilized  by  heat  are  driven  off,  but  their  carbon  remains 
united  to  that  of  the  fibre,  which  is  itself  decomposed,  though 
preserving  its  form. 

Fibre  separated  from  all  other  vegetable  substances  by 
either  of  the  two  first-mentioned  processes,  is  possessed  of 
a  great  degree  of  flexibility,  is  insoluble  in  water  or  alcohol, 
and  burns  with  a  yellow  flame. 

Art  has  succeeded  in  extracting  the  vegetable  fibre  from 
13* 


150  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

a  great  variety  of  plants,  by  separating  from  it  all  those 
substances  which  would  serve  to  hasten  its  putrefaction, 
or  to  diminish  its  flexibility :  thus  when  the  stalks  of  flax, 
hemp,  broom,  nettles,  or  the  leaves  of  the  aloe,  are  mace- 
rated in  water,  all  the  juices  are  extracted  by  dissolution 
and  fermentation,  and  there  remains  only  the  flexible  fibre, 
from  which  fabrics  of  Jinen,  thread,  and  cordage,  so  exten- 
sively used,  are  manufactured. 

The  opinion  which  some  have  entertained  that  those 
stalks,  which  had  been  bruised  by  machinery,  did  not  re- 
quire to  be  softened  by  the  action  of  water,  appears  to  be 
erroneous  :  a  portion  of  the  juices  may,  it  is  true,  be  sepa- 
rated by  mechanical  force,  but  there  remain  some  portions 
which  adhere  so  closely  to  the  fibre,  that  they  can  only  be 
separated  by  maceration  in  water ;  should  these  be  allowed 
to  remain,  they  would  render  the  fibres  unfit  for  many  pur- 
poses, and  would  likewise  be  injurious  to  their  strength. 

The  size  of  the  fibre  is  not  the  same  in  all  the  plants 
I  have  just  mentioned ;  that  of  flax  is  finer,  and  more  deli- 
cate than  the  others  ;  from  this  the  finest  linens,  cambrics, 
and  lawns  are  made.  The  fibre  of  hemp  is  next  in  quality 
to  that  of  flax,  and  is  in  general  use :  some  coarse  fabrics 
are  made  from  the  annual  shoots  of  the  broom ;  and  the  fibre 
of  the  leaves  of  the  aloe  is  manufactured  into  cordage. 

The  fabrics  manufactured  from  vegetable  fibre,  continue 
to  grow  soft  and  pliable  by  use,  till  the  threads  lose  their 
consistency  and  tenacity ;  when  reduced  to  this  state,  they 
are  by  the  action  of  machinery  torn  into  fragments,  and  the 
cohesion  between  the  particles  destroyed  by  means  of  putre- 
fying liquids,  and  thus  a  fluid  paste  is  formed,  of  which  all 
the  particles,  having  no  union  amongst  themselves,  swim 
separately  in  the  water.  These  particles  may,  however, 
upon  being  taken  from  the  water  which  divides  and  sepa- 
rates them,  be  made  to  adhere  strongly  to  each  other  by  a 
series  of  operations  the  execution  of  which  constitutes  the 
art  of  making  paper.  After  having  reduced  the  fibre  to 
a  pulpy  liquid,  the  next  step  is  to  throw  the  liquid  upon 
a  sieve  which  allows  the  water  to  pass  through,  whilst  a 
thin  layer  of  the  paste  remains  adhering  to  the  net-work 
of  the  sieve ;  this  takes  some  consistency  by  being  sepa- 
rated from  the  water  which  held  it  in  solution,  and  its 
firmness  is  further  increased  by  drying :  each  layer  forms 
a  leaf,  which  only  requires  pressing  and  sizing,  to  be  ready 
for  use. 


VEGETABLE    FIBRE.  161 

Though  m  the  manufacture  of  paper,  only  fragments 
which  have  been  thoroughly  rotted  are  made  use  of,  yet 
there  will  be  found  in  the  products  the  same  kind  of  ine- 
quality as  to  fineness,  as  in  the  manufacture  of  cloths :  the 
finest  paper  is  made  from  linen  rags,  the  coarsest  from  the 
remnants  of  ropes. 

Charcoal  consists  almost  entirely  of  the  constituent  prin- 
ciples of  vegetable  fibre,  from  which  the  other  elements 
have  been  separated  by  the  action  of  heat ;  and  as  charcoal 
forms  the  basis  of  vegetable  fibre,  I  cannot  well  avoid  speak- 
ing of  it  in  connexion  with  this  subject ;  and  as  it  is  an 
article  of  such  general  use,  it  ought  surely  to  find  a  place  in 
a  work  of  this  kind. 

The  vegetables  of  which  the  combustion  is  the  most  in- 
tense and  lasting,  are  those  which  in  their  texture  are 
closest  and  driest :  such  give  out  less  flame  in  burning  than 
others,  but  the  heat  is  greater,  and  the  superior  quality  of 
the  coals  produced  from  them  causes  them  to  be  preferred 
for  domestic  heat,  and  for  many  of  the  operations  of  the  arts. 

In  some  manufactures  where  it  is  necessary  to  apply  heat 
to  bodies  which  collectively  form  a  large  mass,  as  in  the 
manufactories  for  porcelain  and  potter's  ware,  in  lime-kilns, 
&c.,  wood  split  fine  and  well  dried  is  preferred,  as  it  gives 
out  much  flame,  and  leaves  but  a  small  residuum  of 
charcoal. 

Those  plants  in  which  the  longitudinal  fibres  are  disposed 
in  closely  compacted  bundles,  possess  all  the  qualities 
necessary  for  combustion  ;  but  the  process  is  much  less  per- 
fect in  those  which  have  not  acquired  this  density,  and  are 
still  full  of  nutritive  juices,  than  in  those  which  have  be- 
come by  age  hardened  into  wood. 

Soil,  exposure,  climate,  and  season  modify  in  a  remarka- 
ble manner  the  fibre  of  vegetables  of  the  same  kind. 

Vegetables  raised  in  a  dry  and  arid  soil  have  a  much  hard- 
er and  more  compact  texture,  than  those  of  the  same  kind 
raised  in  a  moist  and  rich  soil :  they  have  more  perfume, 
contain  a  greater  quantity  of  volatile  oil,  are  decomposed 
with  more  difficulty,  and  during  combustion  give  out  a 
much  more  intense  heat.  Every  one  knows  that  thickets 
having  a  southern  exposure,  yield  better  fuel  than  those 
which  lie  towards  the  north  ;  the  wood  is  more  solid,  and 
after  having  been  cut,  it  will  resist  for  a  longer  time  the 
action  of  air  and  water.  This  fact  was  observed  by  Pliny, 
in  regard  to  the  woods  of  the  Apennines. 


152  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

The  plants  of  southern  climates,  when  transported  to  the 
north,  lose  their  perfume;  and  the  insipid  vegetables  of 
Greenland  acquire  taste  and  smell  when  transplanted  to  the 
gardens  of  the  south  of  Europe. 

In  the  spring  of  the  year,  trees  mo  full  of  juices,  but 
they  yield  at  that  time  principally  mucilage  ;  in  autumn 
they  afford  oil,  starch,  sugar,  &c.  Professor  Plot  remarks, 
that  in  the  year  1692,  trees  cut  in  the  sap  were  devoured 
by  worms,  and  that  the  wood  warped  in  drying  and  ac- 
quired but  little  hardness.  Julius  Csesar  was  convinced  of 
this  truth  when  he  caused  his  vessels  to  be  built  of  wood 
cut  in  the  spring.  And  Vitruvius  advised  that  trees  should 
be  cut  down  only  at  the  close  of  winter,  "  when  the  power 
of  the  cold  shall  have  compressed  and  consolidated  the 
wood." 

Vegetable  fibre  burns  in  the  open  air  with  a  yellow 
flame,  and  disengages  water  and  carbonic  acid  ;  distilled 
in  close  vessels  it  leaves  a  residuum  of  carbon :  it  is  by 
this  process,  that  the  charcoal  used  for  most  purposes  is 
procured. 

The  most  common  method  of  procuring  charcoal  con- 
sists in  cutting  the  branches  and  young  trunks  of  trees  into 
billets  of  about  three  feet  in  length,  and  two  inches  in 
diameter ;  a  portion  of  the  prepared  wood  is  laid  upon  the 
ground  in  parallel  lines,  and  the  remainder  is  piled  upon  it 
in  a  hemispherical  form,  to  the  height  of  six  or  eight  feet ; 
the  surface  is  then  covered  over  with  earth  or  sods  of  grass, 
and  the  pile  set  on  fire  by  means  of  a  flue  in  the  centre. 
In  a  short  time  the  whole  mass  is  heated  through,  and 
water,  carbonic  acid,  and  volatile  oil  are  thrown  out  with 
the  smoke;  this  will  cease  to  appear  when  the  wood  is 
reduced  to  a  black,  sonorous  body,  and  the  pile  may  then 
be  opened. 

This  process  is  very  faulty,  as  in  it  a  great  part  of  the 
wood  intended  to  be  carbonized  is  burned  up,  and  because 
great  skill  is  requisite  for  carbonizing  the  mass  uniformly. 

Wood  reduced  to  charcoal  yields  from  -^jP^  to  -^-^jj  of  its 
weight,  according  to  the  nature  of  the  wood,  and  the  care 
with  which  the  operation  has  been  performed. 

Different  kinds  of  wood  yield  coal  of  very  different 
quality :  the  best  coal  is  heavy  and  sonorous,  and  is  pro- 
duced from  wood  of  very  compact  fibre.  The  heat  it  af- 
fords is  quick  and  strong,  and  its  combustion,  though  vigor- 
ous, lasts  a  long  time.     The  charcoal  of  the  green  oak  of 


VEGETABLE    FIBRE. 


153 


the  south  burns  at  least  twice  as  long  as  that  of  the  white 
oak  of  the  north,  and  the  effects  produced  by  the  heat  it 
affords  are  great  in  the  same  proportion. 

The  light,  porous  white  woods  afford  a  brittle,  spongy 
coal  of  less  weight,  and  which  may  be  easily  reduced  to 
powder  :  this  coal  consumes  quickly  in  our  fire-places,  but 
is  useful  for  some  purposes,  particularly  in  the  manufac- 
ture of  gun-powder,  for  which  use  it  is  prepared  by  the 
following  process  :  a  ditch  of  five  or  six  feet  square,  and 
of  about  four  in  depth,  is  dug  in  a  dry  soil ;  the  ditch  is 
heated  by  means  of  a  fire  made  of  split  wood,  the  shoots 
and  leaves  are  stripped  from  the  young  branches  of  elders, 
poplars,  hazles,  and  willows,  of  which  the  coal  is  to  be 
made,  and  as  soon  as  the  ditch  is  sufficiently  heated  the 
branches  are  thrown  gradually  in ;  when  carbonization  is 
at  its  height,  the  pit  is  covered  over  with  wet  woollen 
cloths.  This  charcoal  is  more  light  and  inflammable  than 
that  of  the  denser  woods,  and  is  susceptible  of  being  more 
easily  and  completely  pulverized.  M.  Proust,  who  has 
made  numerous  experiments  to  ascertain  the  kind  of  plants 
which  furnish  the  best  coal  for  powder,  found  that  pro- 
cured from  the  stalks  of  hemp  to  be  preferable  to  any 
other. 

The  most  perfect  process  of  carbonization  is  performed 
by  means  of  a  close  apparatus  :  for  this  purpose  a  stone  or 
brick  building  is  constructed,  of  from  eighteen  to  twenty- 
five  feet  square  ;  this  is  vaulted  over,  and  the  inside  of  it 
lined  with  a  brick  wall ;  through  the  extent  of  it  cast-iron 
cylinders  are  laid  in  such  a  manner,  that  one  of  the  two 
ends  shall  have  an  external  communication,  whilst  the 
other  carries  the  smoke  into  one  of  the  chimneys.  As  soon 
as  the  building  is  filled  with  the  wood  for  carbonization,  the 
cylinders  may  be  heated.  The  vapor  which  is  distilled 
from  the  wood  is  received  into  sheet-iron  pipes,  placed  in 
the  top,  which  convey  it  into  tubs  where  it  is  condensed. 

The  form  and  dimensions  of  these  buildings  for  making 
charcoal  by  means  of  a  close  apparatus,  are  greatly  va- 
ried, but  of  all  which  I  happened  to  see,  the  one  I  have 
here  described  appears  to  me  the  most  perfect.  There  are 
many  advantages  arising  from  the  use  of  this  method, 
which  more  than  repay  the  necessary  expense  of  the  appa- 
ratus. In  the  first  place,  a  much  greater  quantity  of  char- 
coal is  obtained,  than  by  the  ordinary  process ;  in  the 
second  place,  well  made  and  clean  charcoal  is  always  pro- 


154  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

cured ;  and  in  the  third  place,  there  is  obtained  a  great 
quantity  of  pyroligneous  acid,  which  may  be  sold  for 
$  1.80  or  $  2.16  per  French  hogshead,  and  which,  when 
purified  and  rendered  clear,  may  supply  the  place  of  vinegar 
for  many  purposes. 

In  addition  to  its  very  extensive  usefulness  in  our  work- 
shops and  for  domestic  fires,  charcoal  possesses  the  prop- 
erty of  destroying  disagreeable  smells,  and  of  preventing 
or  retarding  putrefaction  ;  it  is  likewise  useful  in  clarify- 
ing water,  which,  by  being  filtrated  through  it,  loses  the 
bad  odor,  which  it  in  some  instances  possesses.  When 
the  inside  of  a  cask  is  charred  according  to  the  plan  of 
M.  Berthollet,  water  may  remain  in  it  a  long  time  unal- 
tered, and  without  acquiring  any  bad  taste.  I  do  not 
doubt  that  the  same  good  effect  would  be  produced  upon 
wine,  which  often  acquires  from  the  cask  so  disagreeable 
a  taste  as  not  to  be  drinkable. 

An  analysis  of  oak  wood,  and  one  of  beech  also,  gave  to 
Messrs.  Gay-Lussac  and  Thenard  the  following  results. 
100  parts  of  oak  wood, 

Carbon 52.53 

Oxygen 41.78 

Hydrogen      ....       5.69 
100  parts  of  beech  wood. 

Carbon 51.45 

Oxygen     .....     42.73 
Hydrogen      ....       5.82 


ARTICLE   VIII. 

Gluten  and  Albumen. 

Gluten  and  albumen  are  substances,  which,  although 
found  in  the  vegetable  kingdom,  have  all  the  properties  of 
animal  matter ;  they  yield  an  abundance  of  ammonia  by 
distillation  or  putrefaction. 

Gluten  and  albumen,  although  possessing  some  common 
properties,  cannot  be  considered  as  the  same,  as  there  is 
an  essential  difference  between  them. 

Albumen  is  an  insipid  fluid  soluble  in  cold  water,  from 
which  it  may  be  precipitated  by  alcohol,  the  acids,  or  tan- 


GLUTEN   AND    ALBUMEN.  155 

nin ;  but  the  most  distinguishing  characteristic  which  it 
possesses,  is  that  of  coagulating  at  a  degree  of  heat  indi- 
cated by  from  45°  to  50°  of  the  centigrade  thermometer, 
(equal  to  from  113°  to  122°  Fahr.) 

Proust,  Clark,*  Fourcroy,  and  Vauquelin  have  each 
proved  the  existence  of  albumen  in  the  juices  and  fruits  of 
most  plants. 

The  white  of  eggs  consists  of  nothing  but  pure  albu- 
men :  nearly  all  the  different  parts  of  animals  contain  dif- 
ferent portions  of  it ;  it  is,  however,  most  abundant  in  the 
blood. 

Besides  the  property  which  albumen  possesses  of  serv- 
ing as  food,  it  is  employed  for  many  purposes  in  the  arts, 
particularly  for  clarifying  fluids  ;  when  used  for  this,  it  is 
diluted  with  water,  and  then  mixed  with  the  liquid  which 
is  to  be  clarified  ;  the  whole  is  then  heated  to  65°  or  70° 
Fahr.,  and  stirred  carefully  so  as  to  distribute  the  albumen 
equally  amongst  all  its  particles ;  by  increasing  the  heat 
the  albumen  is  made  to  coagulate,  when  it  rises  to  the  top 
of  the  vessel,  carrying  with  it  all  the  particles  which  render 
the  liquid  turbid  or  cloudy ;  the  thick  foam  which  this  pro- 
duces when  cooled,  may  be  taken  off  with  a  skimmer,  and 
the  liquid  be  afterwards  filtrated  to  remove  any  remaining 
particles  from  it. 

The  juice  of  the  fruit  of  the  Hibiscus  Esculentus,  (eat- 
able hibiscus,  Okra^)  contains  so  great  a  quantity  of  albu- 
-tnen,  that  in  St.  Domingo  it  is  employed  in  clarifying 
liquors  ;  in  Martinique  and  in  Guadaloupe  they  make  use 
of  the  bark  of  the  slippery  elm  for  the  same  purpose. 

As  albumen  dries  easily,  and  covers  all  bodies  to  which 
it  is  applied  in  thin  layers,  with  a  smooth  and  shining  var- 
nish, it  is  used  for  giving  lustre  to  paintings,  wainscots,  &c. 

The  albumen  of  eggs  mixed  with  quicklime  finely  pow- 
dered and  spread  upon  strips  of  linen,  makes  an  excellent 
lute,  to  be  applied  over  the  joints  of  vessels  for  distilling, 
where  it  is  necessary  to  avoid  any  loss  of  gas  or  vapor. 
The  white  of  eggs  is  preferred  for  such  purposes,  because 
the  albumen  of  it  is  more  free  from  mixture  than  that  of 
any  other  substance.  An  analysis  of  the  white  of  eggs 
afforded  to  Messrs.  Gay-Lussac  and  Thenard  the  following 
results  :  100  parts  of  the  white  of  an  egg  contained 

Carbon 52.883 

Oxygen 23.872 

Hydrogen    ....       7.540 
Azote 15.705 


166  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Gluten  appears  to  exist  more  extensively  than  albumen 
in  the  vegetable  kingdom ;  it  may  be  extracted  from 
acorns,  chestnuts,  horse-chestnuts,  apples,  quinces,  wheat, 
barley,  rye,  peas,  and  beans;  from  the  leaves  of  the  cab- 
bage, cress,  hemlock,  borage,  and  saffron  ;  from  the  ber- 
ries of  the  elder,  the  juice  of  the  grape,  &lc.  ;  it  is,  how- 
ever, contained  in  the  greatest  quantity  in  the  grain  of 
wheat,  and  it  is  from  this  that  it  is  usually  procured. 

In  order  to  extract  gluten,  the  flour  of  wheat  must  be 
kneaded  into  a  paste  with  water ;  this  paste  must  be  after- 
wards worked  by  the  hand  under  a  stream  of  water  from  a 
spout,  till  the  liquid  flows  off  clear ;  the  starch,  sugar,  and 
all  the  other  principles  contained  in  wheat,  which  are  solu- 
ble in  water,  are  thus  carried  off,  and  there  remains  in  the 
hands  only  a  soft,  elastic,  glutinous,  ductile,  semi-transpa- 
rent substance,  adhering  to  the  fingers  after  it  has  lost  its 
moisture,  and  exhaling  an  animal  odor  ;  this  substance  is 
called  gluten  or  the  vegeto-animal  principle. 

Gluten  is  destitute  of  taste,  turns  brown  in  the  air,  and 
putrefies  in  the  same  manner  as  animal  substances  do ;  it 
is  insoluble  in  alcohol,  and  but  slightly  soluble  in  water. 
Combustion  and  distillation  disengage  from  it  the  same 
products  as  those  furnished  by  animal  matter. 

Wheat  is  composed  almost  entirely  of  starch  and  gluten. 
The  results  of  the  analyses  made  by  Davy,  of  the  wheat  of 
different  countries  is  as  follows  : 

100  parts  of  fall  wheat  of  excellent  quality  gave  of 
starch.     ...     77 
gluten.     .     .     .19 

100  parts  of  spring  wheat 

starch.     ...     70 
gluten.     ...     24        . 

100  parts  of  Barbary  wheat 

starch ....     74 
.    gluten.     ...     23 

100  parts  of  Sicily  wheat 

starch ....     75 
gluten.     ...     21 

The  wheat  of  southern  countries  contains  more  gluten 
than  that  of  the  northern  countries ;  and  the  hard-grained 
wheat  more  than  the  soft-grained  wheat  of  the  same  coun- 
try.    That  wheat  which  contains  the  most  gluten,  ferments 


TANNIN.  157 

the  most  easily  when  made  into  dough ;  it  is  for  this  rea- 
son that  the  Italian  pastes  are  made  of  the  flour  of  the 
hard  wheat  from  the  Crimea,  instead  of  that  from  the 
wheat  of  the  north. 

Amongst  all  the  different  kinds  of  bread  corn,  those 
from  the  flour  of  which  the  best  bread  is  made,  and  of 
which  the  dough  rises  or  ferments  the  most  readily,  are 
those  which  contain  the  most  gluten :  they  may  be  ranked 
in  the  following  order. 

1.  Wheat,  containing  from  y^«^  to  -^^^^  of  its  weight  of 
gluten. 

2.  Barley,  from  y^^-  to  yf^ 

3.  Rye,  from  ^  to  -j^ 

4.  Oats,  from  ^  to  t§^ 

When  grain  or  flour  has  undergone  any  change  by  which 
the  gluten  is  destroyed,  the  bread  made  from  it  is  bad  and 
unwholesome,  and  such  grain  or  flour  should  only  be  em- 
ployed for  making  starch. 

Flour  which  contains  but  little  gluten,  or  which  has  been 
deprived  of  it,  if  made  into  bread,  turns  sour  by  fermenta- 
tion ;  the  dough  does  not  rise,  and  when  baked  is  acid, 
heavy,  and  indigestible. 

There  are  some  very  nutritive  vegetables  in  which  the 
starch,  instead  of  being  combined  with  gluten,  as  it  is  in 
the  bread  corns,  is  united  with  mucilage  ;  this  is  the  case 
in  peas,  beans,  and  potatoes.  The  flour  of  these  will  not 
alone  make  bread ;  but  it  is  frequently  used  in  years  of 
scarcity,  mixed  with  that  of  wheat,  to  increase  the  quantity 
of  bread.  Dough  made  of  flour  thus  mixed  does  not  fer- 
ment so  completely,  as  that  made  entirely  from  wheat 
flour ;  the  bread,  however,  is  well  tasted  and  wholesome, 
and  preserves  its  freshness  for  even  a  fonger  time  than  the 
other. 


ARTICLE   IX. 

Tannin. 

Tannin,   or    the  astringent   principle,   is   contained  in 
a  great  variety  of  vegetables ;  it  is  of  a  brown  color,  high- 
ly astringent,  and  dissolves  readily  both  in  water  and  alco- 
14 


158  CHYMISTRY    APPLfEB    TO    AGRKJULTCRB. 

bol.  Its  predominant  characteristic  is  that  of  affording 
an  insoluble  precipitate  when  added  to  a  solution  of  gela- 
tine. It  combines  with  a  solution  of  iron,  and  forms  a 
black  precipitate.  It  enters  into  the  composition  of  writ- 
ing ink,  and  of  the  greater  part  of  the  black  dyes  for 
cloth. 

Tannin  cannot  be  procured  perfectly  pure  without  a 
great  deal  of  difficulty,  and  the  operations  require  a  de- 
gree of  nicety  which  can  only  be  acquired  by  a  close  ac- 
quaintance with  chymical  manipulation.  For  the  greater 
part  of  the  purposes  to  which  it  is  applied  it  is  not  requi- 
site that  it  should  be  freed  from  all  foreign  substances. 
The  great  affinity  which  tannin  has  for  gelatine  causes 
it  to  combine  with  that  principle  whenever  presented  to  ity 
till  the  substances  containing  the  gelatine  are  completely 
exhausted  of  it :  the  various  proportions  of  tannin  con- 
tained in  the  different  kinds  of  bark  used  in  the  manufac- 
ture of  leather  are  determined  from  this  circumstance. 

The  most  important  purpose  to  which  tannin  is  applied 
is  that  of  converting  skins  into  leather,  and  for  this  pur- 
pose the  tannin  contained  in  the  bark  of  the  oak  is  gener- 
ally preferred.  In  this  process  layers  of  ground  bark  are 
placed  alternately  with  layers  of  skins  in  a  pit,  the  layers 
of  bark  being  slightly  moistened  in  order  that  the  tannin 
mSy  act  readily.  As  the  tannin  combines  with  the  gela- 
tine of  the  skin,  the  latter  changes  its  color  to  a  reddish 
brown,  and  its  opacity  and  consistency  are  at  the  same  time 
increased,  till  by  the  progress  of  the  operation  the  change 
rs  carried  on  through  the  whole  substance  of  the  skin,  and 
it  is  thus  brought  to  the  firmness  of  leather.  This  new 
eombination,  which  consists  entirely  of  a  union  of  tan- 
nin and  gelatine,  is  compact  and  resists  putrefaction  ;  it 
can  be  cut  with  a  knife  by  quick  strokes,  and  employed 
for  numerous  purposes. 

The  best  leather  is  that  which,  by  being  allowed  to  re- 
main in  the  pit  a  long  time,  is  formed  gradually :  in  this 
case  the  slowness  with  which  the  combination  takes  place 
renders  it  more  close  and  complete,  than  when  the  tan- 
nin is  dissolved  in  water  and  the  skins  plunged  into  it. 
By  this  last  process  the  thickest  skin  may  be  tanned  in  a 
few  days,  but  the  quality  of  the  leather  will  be  very 
inferior. 

An  astonishing  improvement  has  been  made  in  the  art 
of  tanning   since  M.  Seguin   discovered  that  it  consisted 


VEGETABLE    ACIDS,  159 

entirely  in  producing  an  union  of  the  astringent  princi- 
ple with  the  gelatine,  which  constitutes  nearly  the  whole 
substance  of  skins  :  since  this  fact  has  been  ascertained, 
tanners  make  use  of  the  liquor  of  tan  which  has  l>een 
once  applied,  but  of  which  the  strength  is  not  exhausted, 
to  moisten  the  bark  in  the  pits,  by  which  the  operation  is 
accelerated,  without  any  injury  to  the  product,  and  leath- 
er is  thus  formed  in  three  or  four  months,  as  completely 
as  it  would  be  in  eighteen  by  the  use  of  the  bark  in  a 
nearly  dry  powder. 

Dry  skins  generally  increase  about  one  third  part  of 
their  weight  by  tanning.  The  different  kinds  of  bark 
used  in  tanning  bestow  various  shades  of  color  upon  the 
leather  produced.     - 

Tannin  has  a  strong  arffinity  for  coloring  principles,  so 
that  in  many  cases  it  serves  as  a  mordant  in  stamping; 
it  is  not  then  surprising  that  leather  should  retain  the  col- 
ors it  receives  so  strongly. 


ARTICLE  X. 

The   Vegetable  Acids, 

I  HAVE  already  observed,  that  when  the  proportions  of 
«xygen  combined  with  hydrogen  are  more  than  sufficient 
for  the  formation  of  water,  the  vegetable  product  will  have 
an  acid  character.  It  can  therefore  be  a  matter  of  but 
little  surprise,  that  we  find  acids  so  abundant  in  the  vege- 
table kingdom. 

The  quantity  of  acid  contained  in  plants  varies  greatly 
during  the  several  stages  of  vegetation,  and  according  to 
the  circumstances  by  which  the  developement  of  the  in- 
dividual is  influenced.  Plants  raised  in  the  shade,  or 
which  grow  in  cloudy,  cold,  or  rainy  seasons,  when  the 
transpiration  of  carbonic  acid  by  the  leaves  cannot  be 
carried  on  for  want  of  the  action  of  the  direct  solar  rays, 
by  which  alone  it  is  produced,  accumulate  the  acid  i^ 
their  vessels,  and  consequently  all  their  products  partake 
of  the  same  general  character.  The  greater  part  of  fruits 
are  sour  before  arriving  at  maturity ;  but  this  is  owing  to 
the  fact,  that  the  mucilage  and  sujgar,  which  are  afterward* 


160  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

found  in  them,  are  not  yet  sufficiently  developed  to  correct 
the  acid  and  disagreeable  taste. 

The  vegetable  acids  which  are  found  most  extensively 
diffused  in  vegetables  are  the  oxalic,  citric,  tartaric,  ben- 
zoic, gallic,  acetic,  malic,  prussic,  &c.  The  analysis  of 
vegetables  presents  a  great  number  of  acids,  but  as  they 
are  found  only  in  particular  kinds  of  plants,  and  their 
uses  are  either  very  limited,  or  altogether  unknown,  I  do 
not  think  it  necesary  to  make  here  an  enumeration  of 
them. 

Most  acids  are  crystallizable,  and  some  of  them  can  be 
-brought  into  a  concrete  state  as  soon  as  they  are  separated 
from  the  other  principles  with  which  they  are  combined  in 
the  plant.  Vinegar,  or  the  acetic  acid,  crystallizes  when 
highly  concentrated  ;  M.  Mollerat  "prepared  crystals  of.  it  as 
transparent  as  ice. 

Oxalic  acid  crystallizes  in  the  form  of  four-sided  prisms : 
the  acid  of  commerce  presents  this  appearance.  M.  Deyeux 
has  found  it  free  in  the  hulls  of  the  chick  pea,  and  it  has 
likewise  been  extracted  from  the  expressed  liquor  of  the 
plant :  it  exists  in  the  stalks  and  leaves  of  sorrel,  and  in  the 
juice  of  all  the  varieties  of  rhubarb. 

It  may  be  produced  by  the  action  of  nitric  acid  upon  most 
vegetable  substances,  especially  sugar. 

Oxalic  acid  is  soluble  in  water  and  alcohol ;  cold  water 
dissolves  one  half  of  its  own  weight ;  boiling  water  a 
weight  equal  to  its  own ;  and  alcohol  ^^j^^  of  its  own 
weight. 

This  acid  possesses  a  strong  affinity  for  the  metallic  ox- 
ides, especially  those  of  iron  ;  it  has  also  the  characteristic 
property  of  depriving  other  acids  of  lime  combined  with 
them,  and  of  forming  with  it  an  insoluble  salt ;  and  it  is 
upon  these  qualities  that  its  use  in  the  arts  is  principally 
founded. 

Oxalic  acid  thrown  into  water  containing  any  calcareous 
salt,  causes  the  liquor  to  become  turbid,  and  forms  from  it  a 
deposit  which  is  found  to  be  the  oxalate  of  lime.  If  the 
oxalate  of  ammonia  be  made  use  of  for  the  above  purpose, 
the  action  will  be  more  speedy  than  if  the  oxalic  acid  be 
ufeed  pure  ;  because  decomposition  is  accelerated  by  the 
exchange  of  principles  constituting  the  two  salts. 

The  power  which  oxalic  acid  possesses  of  dissolving 
readily  the  oxide  of  iron,  renders  it  exceedingly  useful  in 
the  manufacture   of   stamped    goods,    especially   of  cotton 


VEGETABLE    ACIDS,  161 

clolhs.  In  this  process  the  whole  fabric  is  covered  with  a 
mordant  of  iron,  which  is  afterwards  removed  by  means  of 
this  acid  combined  with  gum,  so  that  the  color  applied  ad- 
heres firmly  only  to  those  parts  where  the  mordant  has  not 
been  destroyed:  this  process  is  conducted  with  far  more  ease 
than  that  which  was  formerly  practised,  of  applying  the 
mordant  with  the  block,  reserving  those  parts  untouched 
which  were  not  to  receive  a  fixed  color. 

The  oxalic  acid  is  better  than  any  other  for  removing 
ink  spots  from  cloth  :  it  is  only  necessary  for  this  purpose 
to  put  a  little  upon  the  spot,  and  to  moisten  it  with  a  drop 
of  water,  after  which  a  slight  rubbing  with  the  hand  and 
a  little  rinsing  in  pure  water  removes  every  vestige  of  the 
stain. 

Messrs.  Gay-Lussac  and  Thenard  obtained,  from  an  an- 
alysis of  oxalic  acid,  carbon,  oxygen,  and  hydrogen,  in  the 
following  proportions. 

100  parts  of  oxalic  acid, 

Carbon 26.566 

Oxygen 70.689 

Hydrogen    ....      2.745* 

Tartaric  acid  may  be  extracted  from  the  juice  of  th« 
mulberry,  grape,  currant,  &c.  This  acid  is  almost  always 
found  in  vegetables  combined  with  potassa,  with  which  it 
forms  a  nearly  insoluble  salt :  it  is  this  union  which  occa- 
sions it  to  be  so  easily  precipitated  from  the  liquors  in  which 
it  is  contained,  especially  when  they  ferment.  The  coats  of 
tartar  which  are  found  deposited  upon  the  sides  of  casks 
are  a  combination  of  tartaric  acid,  potassa,  and  extractive 
matter. 

When  tartar  and  the  lees  of  wine  are  burned  together, 
they  leave  alight,  grayish,  alkaline  residuum,  known  in  com- 
merce under  the  name  ot  tartarated  ashes  ;  this  product  has 
its  particular  use  in  the  arts. 

The  crystallized  substance  known  in  commerce,  and 
extensively  used,  under  the  name  of  cream  of  tartar^  is 
prepared  by  dissolving  tartar  in  water  containing  pipe- 
clay ;  this  solution,  after  having  been  filtrated,  is  carefully 
evaporated  till  crystallization  takes  place ;  a  part  of  the 
extractive  matter  of  the  tartar  is  separated  and  falls  to  the 
bottom  of  the  vessel,  the  rest  remains  in  solution.  The 
crystals  thus  obtained  are  composed  of  potassa  with  an 

[•  By  the  best  analysis  no  hydrogen  is  found  in  oxalic  acids.  —  Tb.J 
14* 


162  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

excess  of  tartaric  acid  ;  when  exposed  to  the  air  upon  cloths 
they  acquire  a  brilliant  whiteness. 

From  this  last  combination  tartaric  acid  may  be  extracted 
by  the  following  process,  for  which  we  are  indebted  to 
Scheele.  Dissolve  cream  of  tartar  in  boiling  water,  and 
saturate  the  solution  with  chalk  ;  a  precipitate  of  lime  com- 
bined with  the  acid  will  be  thrown  down ;  this  must  be 
separated,  and  sulphuric  acid  poured  upon  it  in  the  propor- 
tion of  one  third  of  the  weight  of  cream  of  tartar  employed  ; 
to  this  mixture  apply  a  gentle  heat  for  ten  or  twelve  hours  ; 
the  sulphuric  acid  will  combine  with  the  lime  and  form  an 
insoluble  precipitate,  whilst  the  tartaric  acid  will  be  set  free 
and  swim  above  it ;  the  whole  must  then  be  diluted  with 
cold  water,  and  the  liquor  filtrated  and  evaporated  to  the 
consistency  of  a  sirup,  when  the  tartaric  acid  will  be  pre- 
cipitated in  a  concrete  state.  When  evaporation  is  carried 
on  slowly  and  the  sirup  allowed  to  remain  at  rest,  the  acid 
crystallizes  in  long  octahedrons  :  if  these  crystals  be  purified 
by  being  repeatedly  dissolved,  and  the  solution  filtrated  and 
evaporated,  they  become  very  white,  and  present  the  form  of 
tetrahedral  prisms,  terminated  by  pyramids  of  four  elongated 
faces. 

Tartaric  acid  is  composed  of 

Carbon        24.050 

Oxygen 69.321 

Hydrogen 6.629 

One  of  the  acids  most  extensively  found  in  the  vegeta- 
ble kingdom  is  the  malic;  this  differs  essentially  from 
the  two  of  which  I  have  just  spoken,  in  remaining  always 
in  a  liquid  state,  and  forming  with  lime  a  salt  soluble  in 
water. 

Malic  acid  may  be  procured  by  saturating  the  juice  of 
apples  with  potassa,  and  decomposing  the  salt  thus  formed 
by  means  of  the  acetate  of  lead  :  the  precipitate  thus  pro- 
duced must  be  washed,  after  which  sulphuric  acid  must  be 
poured  upon  it  till  the  liquor  retains  no  sweetish  taste  :  an 
insoluble  sulphate  of  lead  is  formed,  which  may  be  separated 
from  the  malic  acid  by  filtration.  Scheele,  by  whom  this 
acid  was  discovered,  has  made  many  experiments  to  ascertain 
its  existence  in  vegetables. 

Malic  acid  is  found  most  abundantly  in  apples,  barberries, 
plums,  and  sour  grapes;  red  fruits  furnish  less  of  it,  but  it  is 
found  in  a  greater  or  less  quantity  in  nearly  all  the  products 
of  vegetation. 


VEGETABLE    ACIDS.  '  163 

This  acid  exists  naturally  in  all  wines,  but  it  is  more 
abundant  in  those  of  the  north  than  in  those  of  the  south  ; 
it  predominates  in  them  when  made  of  unripe  grapes, 
or  if  the  must  have  been  badly  fermented.  White  grapes 
contain  less  malic  acid  than  red  ones,  and  I  believe  the 
superiority  of  the  liquor  obtained  from  the  first  ought  to 
be  referred  to  this  difference.  Brandy  made  from  wine 
abounding  in  this  acid,  turns  vegetable  blues  red,  and  is 
of  a  bad  quality.  Malic  acid  has  not  as  yet  been  made  use 
of  in  the  arts. 

Citric  acid  is  found  in  large  quantities  in  oranges-  and 
lemons,  particularly  in  the  last ;  the  skins  of  wild,  hairy 
plums,  the  red  currant,  cherries,  strawberries,  and  rasp- 
berries likewise  contain  it ;  in  these  it  is  found  united  with 
malic  acid  in  nearly  equal  proportions. 

The  process  given  us  by  Scheele  for  obtaining  and 
crystallizing  citric  acid,  is  the  one  we  still  make  use  of;  the 
acid  is  saturated  with  lime,  and  the  insoluble  salt  thus  formed 
is  decomposed  by  sulphuric  acid  diluted  with  water;  the 
liquor  is  then  evaporated  and  the  acid  obtained  in  a  crystal- 
line form  :  by  being  repeatedly  dissolved,  filtrated,  and 
evaporated,  the  crystals  are  produced  in  the  form  of  rhom- 
boidal  prisms,  of  which  the  inclined  planes  are  terminated 
at  each  end  by  a  summit  of  four  trapezoidal  faces. 

In  Sicily  and  some  other  countries  where  lemons  grow  in 
profusion,  it  is  customary  to  extract  the  juice  of  the  fi-uit 
and  saturate  it  with  lime;  this  citrate  is  afterwards  sent  to 
the  places  where  it  is  to  be  consumed,  and  there  the  opera- 
tion of  extracting  the  acid  is  terminated.  The  great  quan- 
tity of  mucilage  which  the  juice  of  the  lemon  contains,  pre- 
vents it  from  being  kept  for  a  long  time,  or  conveyed  to  any 
considerable  distance,  without  undergoing  changes  that  affect 
its  nature. 

The  process  of  pressing  the  lemons  is  begun  in  November, 
and  ended  in  March :  the  quantity  of  juice  extracted  de- 
pends on  the  ripeness  of  the  fruit.  The  liquor  is  put  into 
barrels,  and  either  sent  off,  or  what  is  preferable,  sold  on  the 
spot  to  individuals  engaged  in  manufacturing  it  into  the 
citrate  of  lime,  in  order  to  prevent  the  decomposition,  which 
exports  of  this  nature  always  undergo. 

About  2V  of  carbonate  of  lime  is  required  to  saturate 
a  given  weight  of  lemon  juice :  the  citrate  is  carefully 
washed,  and  afler  being  dried  is  sent  to  its  place  of  desti- 
nation. 


164  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

When  nothing  more  than  the  extraction  of  the  citric 
acid  is  required,  the  process  is  conducted  in  the  following 
manner.  Sulphuric  acid  diluted  with  six  or  seven  times 
its  weight  of  water  is  thrown  upon  the  citrate,  the  mixture 
being  stirred  as  the  citrate  is  turned  in ;  when  decomposi* 
tion  has  fully  taken  place,  the  citric  acid  swims  above  the 
insoluble  sulphate  of  lime  which  has  been  formed;  the 
whole  is  filtrated  and  the  deposit  washed  ;  the  water  of  the 
washing  is  added  to  the  acid,  and  evaporation  is  carried 
on  in  pewter  vessels :  this  operation  may  be  commenced 
by  boiling  the  liquor  rapidly,  but  in  proportion  as  this 
becomes  thickened  the  action  must  be  diminished ;  when 
the  acid  has  acquired  the  consistency  of  a  sirup  it  is  re- 
moved from  the  fire  and  left  to  crystallize.  After  the 
crystals  have  been  removed  from  the  mother  icater,  ten  or 
twelve  times  its  own  weight  of  water  is  added  to  it,  and  it  is 
then  treated  in  the  same  manner  as  the  lemon  juice. 

In  order  to  obtain  the  crystals  of  citric  acid  perfectly 
pure,  it  is  necessary  to  repeat  the  processes  of  solution, 
filtration,  and  evaporation,  several  times.  When  these 
operations  are  skilfully  performed,  the  juice  of  the  lemon 
yields  about  ^  of  its  weight  in  citrate  of  lime,  and  -^^  of 
citric  acid  in  crystals. 

Citric  acid  is  very  soluble  in  water,  and  advantageously 
supplies  the  place  of  lemon  juice  for  domestic  purposes, 
and  in  the  arts,  both  by  its  being  freed  from  mucilage, 
which  renders  the  juice  liable  to  undergo  speedy  changes, 
and  from  the  diminution  of  its  bulk  by  concentration. 

To  give  a  flavor  to  food,  citric  acid  is  much  more  agreea- 
ble than  vinegar,  on  account  of  the  aromatic  particles  it 
contains ;  dissolved  in  water  it  forms  a  very  wholesome 
drink  :  about  30  grains  of  this  acid  dissolved  in  a  pint  of 
water  and  sweetened  with  sugar,  composes  an  excellent 
lemonade.  From  its  refreshing  and  antiputrescent  proper- 
ties, it  is  invaluable  during  the  hot  months,  and  especially  as 
an  article  for  sea  stores  of  vessels  in  warm  latitudes. 

Citric  acid  has  also  its  peculiar  uses  in  the  arts;  likethe 
oxalic  acid,  it  is  employed  in  forming  reserves  in  printed 
goods,  and  in  removing  spots  of  ink  or  rust. 

When  the  coloring  principle  of  the  saffron  (carthamus 
tinctorius)  is  dissolved  by  an  alkali  and  precipitated  by 
citric  acid,  it  produces,  upon  silk,  an  orange,  scarlet,  or 
light-red  color ;  when  thrown  down  in  the  same  manner 
upon  a  white,  oily  surface,  it  constitutes  the  vegetable  red 
or  rouge. 


VEGETABLE    ACIDS. 


165 


The  constituent  principles  of  citric  acid  are  found  in 
the  following  proportions; 

Carbon 33.811 

Hydrogen        6.330 

Oxygen 59.859 

Acetic  acid  exists  ready  formed  in  the  sap  of  plants ; 
it  is  sufficiently  distinguished  from  all  the  other  vegetable 
acids  by  the  peculiar  property  it  possesses  of  forming 
easily  soluble  salts  with  the  earths  and  alkalies. 

When  a  plant  or  any  other  vegetable  product  is  distilled, 
not  only  the  acetic  acid  which  it  contains  is  extracted 
from  it,  but  a  great  quantity  of  acid  is  formed  by  that  de- 
composition and  disunion  of  the  constituent  principles, 
which  is  produced  by  heat.  The  smoke  which  escapes 
from  our  fire-places  is  only  a  confused  mixture  of  water, 
acetic  acid,  oil,  carbonic  acid,  and  carbon. 

The  acid  produced  by  combustion  and  distillation  has 
been  known  for  a  long  time  under  the  name  of  pyroligneous 
acid :  it  was  not  suspected  to  be  the  same  as  vinegar. 

A  vast  quantity  of  this  acid  may  be  procured  with  great 
ease  by  the  new  method  of  carbonizing  wood  in  close 
vessels :  the  acid  thus  procured  is  however  combined 
with  oil,  which  gives  it  a  dark  brown  color,  and  a  disa- 
greeable empyreumatic  odor;  but  by  a  particular  process 
it  may  be  freed  from  all  foreign  matter,  and  rendered 
perfectly  pure  :  to  effect  this,  the  acid  must  be  saturated 
with  lime  or  an  alkali ;  after  which  the  oil  must  be  car- 
bonized by  exposing  the  i>ew  salt  impregnated  with  it,  to 
a  degree  of  heat  sufficient  to  effect  that  change ;  the  salt 
is  then  to  be  decomposed  by  pouring  upon  it  sulphuric 
acid ;  or,  the  same  result  may  be  obtained  by  decompos- 
ing the  acetate  of  lime  by  means  of  an  alkaline  sulphate : 
in  this  case  an  exchange  of  bases  takes  place,  and  the 
acetate  treated  with  sulphuric  acid  furnishes  a  very  pure 
acid.* 

*  Wood  is  distilled  in  a  great  iron  retort,  the  bottom  of  which  is 
of  cast  iron,  and  the  sides  of  thick  sheet  iron  ;  when  it  is  filled  with 
wood  the  lid  of  it  is  carefully  luted  on  with  clay. 

For  distillation  the  wood  must  be  very  dry  and  the  sticks  prepared 
of  equal  thickness.  Each  retort  will  contain  two  ^' votes"  (  =  106 
cubic  feet)  of  wood.  The  opening  or  flue  by  which  the  smoke  es- 
capes, is  placed  at  a  distance  of  some  inches  from  the  bottom  of  the 
boiler  or  retort.  The  acid  is  carried  by  copper  pipes  into  a  vessel,  in 
which  the  water  is  constantly  renewed  :  the  acid  and  tar  flow  by  a 
cock  into  a  close  vessel.     The  inflammable  gas  passes  through  copper 


lOljS  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

The  acid  procured  in  this  manner  has  some  very  great 
advantages  over  that  obtained  by  the  acidification  of  fer- 
mented liquors ;  this,  being  distilled,  is  consequently  puri- 
fied from  any  foreign  substance,  and  can  be  thrown  into 
the  market  in  so  concentrated  a  state,  as  to  render  it 
much  more  active  than  vinegar  of  wine,  and  capable  of 
producing  effects  which  it  is  difficult  to  obtain  from  that. 

Even  to  the  present  day,  all  the  acetic  acid  employed 
either  for  domestic  purposes,  or  in  the  numerous  opera- 
tions carried  on  in  the  workshops  of  the  various  arts,  has 
been  provided  by  the  degeneration  or  decomposition  of 
fermented  drinks,  such  as  wine,  beer,  cider,  perry,  &.c.  : 
all  these  liquors  are  more  or  less  spirituous,  and  contain  a 
portion  of  mucilage,  which  tends  continually  to  produce  in 
them  the  acetous  fermentation. 

To  prevent  the  acidification  of  wine,  the  liquor  should 
be  put  up  in  good  casks,  well  stopped,  and  placed  in  a  cool 
place,  of  which  the   temperature   does   not   sensibly  vary ; 

tubes  into  the  fire-place,  to  heat  the  cylinder  and  increase  the  carbo- 
nization. 

The  process  of  carbonization  lasts  five  hours  ;  the  cooling  is  com- 
pleted in  about  seven. 

The  acid  thus  produced  is  very  impure,  but  serves  for  the  prepara- 
tion of  pyrolignites  of  iron  :  in  order  to  purify  it,  it  must  be  put  into  an 
iron  boiler,  saturated  while  cold  with  chalk,  and  the  tar,  which  will  rise 
to  the  top,  skimmed  off;  the  liquor  must  then  be  poured  into  another 
boiler,  heated  to  ebullition,  and  the  saturation  continued  up  to  this 
point;  sulphate  of  soda  is  afterward  added,  when  there  is  formed 
sulphate  of  lime,  which  is  precipitated,  and  acetate  of  soda,  which 
remains  in  solution.  The  liquor  must  then  be  drawn  off  and  evapo- . 
rated  till  pellicles  are  formed,  when  it  is  thrown  into  large  tubs,  where 
it  acquires  solidity  by  cooling. 

An  igneous  fusion  of  this  mass  has  been  produced  by  heating  it 
in  a  cast-iron  boiler,  till  the  water  was  all  evaporated,  and  aflerwards 
continuing  the  fusion  to  ignition ;  the  liquor  was  then  poured  into 
moulds  in  which  it  solidified ;  in  this  state  it  is  black,  and  easily 
soluble  in  hot  water :  a  solution  of  it  well  filtrated  and  evaporated 
yields  crystals  of  a<;etate  of  soda,  which  retain  almost  nothing  of  the 
empyreumatic  odor.  When  these  crystals  are  dissolved  in  water,  and 
the  solution  decomposed  by  sulphuric  acid,  crystals  of  sulphate  of 
soda  are  obtained,  and  acetic  acid,  which  only  requires  distillation  to 
be  perfectly  pure ;  the  acid  then  marks  from  eight  to  ten  degrees  of 
the  aerometer  of  Baume,  (  =  specific  gravity  of  1.060  to  1.075.)  To 
obtain  the  acid  in  a  crystalline  state,  it  is  sufficient  to  combine  it 
with  lime,  and  to  decompose  by  sulphuric  acid  this  salt  slightly  cal- 
cined :  the  sulphate  of  lime  takes  nearly  all  the  water  which  re- 
mains in  the  acetate. 

The  mother  water  of  the  first  operations,  evaporated  to  dryness  and 
mixed  with  tar,  serves  as  a  combustible ;  the  ashes  passed  through  a 
reverberatory  furnace  and  afterwards  leached  affords  very  fine  sub- 
earbonate  of'^soda. 


VEGETABLE    ACIDS.  t0T 

it  should  be  clarified  in  order  to  free  it  from  the  mucilage, 
which  would  cause  it  to  ferment ;  and  care  must  be  taken 
so  to  place  the  casks,  that  the  liquor  will  not  be  liable,  by 
being  jolted,  or  shaken,  to  have  the  mucilage,  which  has 
been  precipitated,  mixed  again  with  it. 

When  wine  has  been  well  fermented,  and  all  its  muci- 
lage decomposed  or  precipitated,  it  is  no  longer  capable  of 
turning  sour.  I  Jiave  kept  some  of  the  red  wine  of  the 
south  in  uncorked  bottles,  upon  a  terrace  exposed  to  the 
heat  of  the  sun  during  a  whole  summer,  without  its  under- 
going any  other  change  than  that  of  completely  losing  its 
color ;  the  coloring  principle  being  precipitated  in  the  form 
of  pellicles  or  membranes,  which  remained  swimming  in  the 
liquor.  Towards  the  end  of  August,  I  put  into  two  of  these 
bottles,  containing  equal  quantities,  the  juice  of  two  apples, 
and  at  the  end  of  a  month  the  liquor  was  converted  into 
vinegar. 

The  care  which  is  necessary  to  preserve  wine  unchang- " 
ed,  indicates  the  course  to  be  pursued  for  converting  it  into 
vinegar  :  all  that  is  required  to  accomplish  this,  is  to  expose 
the  liquor  to  the  air  at  a  temperature  of  between  70°  and  80° 
Fahrenheit :  when  the  liquor  does  not  contain  any  fermenta- 
tive matter,  a  portion  of  yeast  may  be  added  to  it;  or  it  may 
be  put  into  casks,  which  are  impregnated  with  acetic  acid  or 
which  contain  sour  lees. 

I  shall  not  undertake  to  enumerate  the  various  uses  to 
which  vinegar  is  applied  upon  our  tables,  or  in  our  kitch- 
ens ;  its  employment  in  the  arts  is  at  least  as  extensive 
and  as  varied;  aromatic  plants  are  distilled  with  it  for 
perfumes,  and  it  is  used  for  dissolving  iron,  copper,  lead, 
and  alumine,  to  form  mordants  in  dyeing,  and  colors  in 
stamping. 

Messrs.  Gay-Lussac  and  Thenard  found  acetic  acid  to 
contain  carbon,  oxygen,  and  hydrogen  in  the  following 
proportions ; 

Carbon .     50.224 

Hydrogen 5.629 

Oxygen 44.147 

Prussic  Acid.  Bitter  almonds,  peach-  stones,  and  the 
leaves  of  the  laurel,  when  distilled,  afford  an  acid,  which 
forms,  with  a  solution  of  iron  and  a  small  quantity  of  alka- 
li, a  greenish  blue  precipitate  :  this  acid  bears  a  strong 
resemblance  to  that  which  is  extracted  from  some  animal 
substances,  and  which,  when  combined  with  iron,  forms 
Prussian  blue. 


168  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

M.  Gay-Lussac,  who  has  made  a  series  of  experiments 
upon  prussic  acid,  found  it  to  consist  of  carbon,  azote, 
and  hydrogen,  combined  in  the  following  proportions  ; 

Carbon 44.39 

Azote 51.71 

Hydrogen 3.90 

The  two  first  elements  of  this  composition  form  a  radi- 
cal, which  our  distinguished  author  calls  cyanogen :  the 
combination  of  this  with  hydrogen  constitutes  the  prussic 
or  hydrocyanic  acid.  There  exists  in  this  acid  no  trace 
of  oxygen,  nor  is  it  the  only  instance  of  the  kind,  which 
modern  chymistry  affords  us. 

Combined  with  iron,  prussic  acid  forms  the  valuable 
substance  known  by  the  name  of  Prussian  blue,  the  use 
of  which  is  so  important  in  coloring  and  painting.  M.  Ray- 
mond has  discovered  a  method  of  fixing  this  color  so 
successfully  upon  silk,  that  indigo  has  almost  disappeared 
from  the  coloring  establishments  of  Lyons :  a  son  of 
M.  Raymond  has  been  equally  successful  in  his  use  of  it 
for  woollen  manufactures. 

The  vegetable  kingdom  furnishes  many  other  acids,  as 
the  benzoic,  gallic,  mucic, .  kinic,  &c. ;  but  as  they  are 
less  abundant,  and  their  uses  very  limited,  I  do  not  think 
it  necessary  to  give  here  any  account  of  them. 


ARTICLE   XI. 

The  Fixed  Alkalies. 

Potash  is  found,  in  greater  or  less  quantities,  in  all 
vegetables ;  soda  generally  in  plants  growing  near  the 
sea,  or  in  soils  impregnated  with  marine  salt. 

The  most  convenient  mode  of  obtaining  potash  is  by 
burning  vegetable  substances,  leaching  the  ashes,  and 
evaporating  a  solution  of  them  to  dryness  :  this  first  prod- 
uct is  known  under  the  name  of  salts,  and  is  employed  in 
the  arts;  it  is  colored,  but  becomes  white  by  being  cal- 
cined in  a  reverberating  furnace  ;  it  is  then  known  by  the 
name  of  pearlash. 

As  the  use  of  the  salts  and  of  pearlash  in  the  arts  is  very 
extensive,  and  as  there  are  few  localities  where  they  may 


FIXED   ALKALIES.  169 

not  be  advantageously  made,  I  have  been  of  opinion,  that 
a  farmer  might  easily  unite  the  manufacture  of  them  to  his 
agricultural  labors,  and  thus  increase  the  income  arising 
from  his  lands:  I  shall  therefore  enter  into  some  details 
respecting  it. 

All  plants  do  not  yield  the  same  quantity  of  ashes,  nor 
do  equal  weights  of  the  ashes  of  different  plants  afford  the 
same  quantity  of  potash.  Of  the  comparative  value  of  cer- 
tain vegetables,  we  may  judge  from  the  following  Tables, 
prepared  from  the  experiments  of  Messrs.  the  Superin- 
tendents-general of  the  powder  and  salt-petre  works,  for 
the  year  1779,  and  from  those  of  Messrs.  Kir  wan,  Pertuis, 
and  Vauquelin. 

15 


170 


cHymistry  applied  to  agriculture. 


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Lead  ore. 
Gridelin. 
Coffee  with 
Grayish  whi 
Wine  gray. 
Deep  black. 
Rusty  black 
Whitish  gra 
Yellowish  w 
Ash  color. 

Color 

of  the 

salt. 

B-.^  •            ^B 

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FIXED    ALKALIES. 


171 


The  salt  obtained  by  these  operations  loses  by  calcina- 
tion, in  order  to  convert  it  into  pearlash,  25  or  30  per  cent, 
of  its  weight. 

The  results  of  the  experiments  made  by  Kirwan  upon 
1000  lbs.  of  each  of  the  vegetables  assayed,  are  as  follows. 


Name  of  the  vegetable. 

Product  in  ashes. 

Product  in  alkali. 

Stalks  of  maize     .     .     . 

88.00 

17.05 

Giant  sun-flower  .     .     . 

57.02 

20.00 

Branches  of  the  vine .     . 

34.00 

5.05 

Box 

29.00 

2.26 

Willow 

28.00 

2.85 

Elm 

23.05 

3.09 

Oak 

13.05 

1.05 

Aspen     

12.02 

0.74 

Beech     

5.08 

1.27 

Fir     ....... 

3.04 

0.45 

Fern,  in  August    .     .     . 

36.46 

4.25 

Wormwood 

97.44 

73.00 

Fumitory 

219.00 

79.00 

Table  of  Mean  Results  of  the  Experiments  of  Messrs.  Kir- 
wany  Vauquelin,  and  Pertuis,  upon  10,000  parts  of  each 
plant. 

Elm 39  of  potash. 

Oak 15 

Beech 12 

Vine 55 

Poplar 7 

Thistle 53 

Fern 62 

Cow  thistle 196 

Wormwood 730 

Vetches 275 

Beans 200 

Fumitory 790 

In  selecting  plants  to  burn  for  potash,  it  is  advisable  to 
choose  those  that  contain  the  most  of  it ;  grasses,  leaves, 
the  stalks  of  French  beans,  of  peas,  melons,  gourds,  cab- 
bages, artichokes,  potatoes,  maize,  and  garget,  are  very 
rich  in  this  alkali.  The  plants  are  first  dried,  and  then 
burned,  and  the  ashes  leached. 


172  CHYMISTRY    APPLIED    TO   AGRICULTURE. 

The  operation  is  very  simple :  a  tub  is  filled  with  ashes, 
upon  which  water  is  thrown  till  it  stands  upon  the  top ;  in 
the  course  of  a  few  hours  the  water  filtrates  through  the 
ashes,  and  flows  off  by  a  vent  in  the  bottom  of  the  tub : 
this  ley  should  mark  10°  or  12^  of  the  aerometer  of  Baume. 
(Sp.  gr.  1.075  to  1.091.)  The  first  leaching  does  not  ex- 
haust the  ashes  entirely  of  all  their  alkali,  and  fresh  water 
is  therefore  passed  through  them  till  they  contain  nothing 
soluble :  this  weak  ley  is  added  to  new  ashes,  till  it  ac- 
quires a  suitable  degree  of  strength. 

The  leached  ashes  form  an  excellent  manure  for  damp 
or  clayey  soils;  and  it  is  used  advantageously  in  the  manu- 
facture of  black  glass. 

Ley  is  most  readily  formed  by  using  hot  water,  but  I 
have  confined  myself  to  pointing  out  the  simplest  means 
for  accomplishing  the  purpose,  and  those  that  require  the 
least  apparatus. 

The  ley  is  a  solution  of  potash,  which  may  be  extracted 
from  it  by  evaporation  :  this  process  may  be  commenced 
in  a  copper  boiler,  into  which  a  very  fine  stream  of  the  ley 
should  flow  to  replace  that  which  evaporates :  when  the 
liquor  has  acquired  the  consistency  of  honey,  it  should  be 
put  into  iron  boilers  to  complete  the  operation.  As  the  sub- 
stance thickens,  care  must  be  taken  to  remove  that  por- 
tion of  it  which  adheres  to  the  sides,  and  to  stir  the  whole 
carefully  with  iron  spatulas.  When  the  substance  con- 
geals and  becomes  solid  upon  being  exposed  to  the  air,  it 
is  poured  into  casks  and  thrown  into  commerce  under  the 
name  of  salts. 

The  whole  process  is  simple,  and  may  be  conducted 
upon  our  farms  without  any  difiiculty.  The  farmer  can 
appropriate  to  himself  this  branch  of  industry  without  in- 
terrupting the  usual  course  of  his  labors  :  broom,  heath, 
thistles,  ferns,  brambles,  nettles,  &c.  may  be  collected 
during  the  days  when  agricultural  business  cannot  go  on, 
and  in  the  dead  season,  and  in  the  winter  they  may  be 
burned,  and  the  ashes  leached. 

I  do  not  propose  to  any  farmer  to  calcine  the  salts,  to 
reduce  them  to  real  potash,  because  he  would  need  for  this 
purpose  a  reverberating  furnace,  and  the  process  would  be 
one  at  variance  with  his  customary  employments.  The 
salts  are  already  applied  to  numerous  uses  in  the  arts  : 
if  the  manufacture  of  them  should  become  a  domestic  one, 
there  would  very  soon  be  establishments  formed  for  covt- 


FIXED    ALKALIES. 


rt3 


verting  the  salts  into  pearlash,  and  thus  extending  the  em- 
ployment of  it. 

The  salts  and  pearlash  contain  all  the  soluble  salts  that 
are  found  in  ashes.  M.  Vauquelin,  who  has  analyzed  the 
various  kinds  of  potash  of  commerce,  with  reference  to 
the  difference  in  their  qualities,  has  obtained  the  following 
results.  1112  parts  of  each  kind  were  subjected  to  ex- 
periment. 


Real 

Sulphate 

Muriate 

Insolu- 

Carbonic 

Potash. 

quantity 

of 

of 

ble  re- 

acid and 

of  alkali. 

potassa. 

potassa. 

siduum. 

water. 

From  Russia 

772 

65 

5 

56 

234 

From  America 

857 

154 

20 

2« 

129 

Pearlash 

754 

80 

4 

6 

308 

From  Dantzick 

603 

152 

14 

79 

304 

From  Vosges 

444 

148 

10 

34 

304 

The  salts  and  pearlash  are  much  used  in  the  arts  :  they 
form  the  basis  of  the  soft  soaps,  and  enter  into  the  compo- 
sition of  white  glass  :  they  are  used  in  washing  and  bleach- 
ing :  they  are  greatly  employed  in  coloring,  metallic  cast- 
ings, the  manufacture  of  salt-petre  and  alum :  in  short, 
there  are  few  manufacturing  establishments,  in  which 
they  are  not  consumed  in  greater  or  less  quantities. 

Soda  exists  in  nearly  all  plants  which  grow  in  a  soil  im- 
pregnated with  marine  salt ;  but  all  of  these  do  not  furnish 
it  equally  pure,  nor  in  the  same  quantity. 

The  barilla  (the  calsola  vermiculata  of  Linnaeus)  is  cul- 
tivated in  Spain  for  the  purpose  of  extracting  from  it  the 
Alicant  soda,  which  is  one  of  the  kinds  most  esteemed  in 
commerce ;  in  nearly  all  the  other  countries  lying  upon 
the  sea  or  upon  the  salt  lakes,  the  plants  growing  upon 
their  coasts  are  burned,  in  order  to  obtain  from  them  this 
substance.  The  different  kinds  of  soda  contain  different 
quantities  of  alkali,  according  to  the  character  of  the  plants 
from  which  they  are  procured ;  hence  arises  a  great  dif- 
ference in  their  n^mes,  prices,  and  uses. 

For  the  manufacture  of  soda,  the  marine  plants  are 
gathered  at  the  season  when  their  vegetation  has  termi- 
15* 


1^4 


CHYMISTRY    APPLIED    TO    AGRICULTURE. 


Dated,  and  (hey  are  left  to  dry :  a  pit  four  feet  square  amf 
three  feet  deep  is  dug  in  the  earth ;  this  is  heated  with 
split  wood,  and  the  saline  plants  are  afterwards  thrown 
gradually  in :  combustion  is  continued  during  seven  or 
eight  days ;  the  ashes  become  fused  in  the  pit,  and  remain 
in  this  state  till  the  end  of  the  process :  when  the  combus- 
tion is  completed^  the  whole  is  allowed  to  cool,  and  then 
the  block  of  soda  ig  divided  into  large  pieces  for  the  market. 

I  have  always  observed  that  when  this  mass  of  soda 
bubbles  up  in  the  pit,  there  escape  from  the  surface  jets 
of  flame  which  appear  to  arise  entirely  from  the  combus- 
tion of  sodium ;  the  perfect  resemblance  which  the  flame 
bears  to  that  of  the  burning  metal,  struck  me  very  forci- 
bly when  I  saw  sodium  burned  for  the  first  time. 

The  plants  which  are  most  commonly  burned  for  ob- 
taining soda,  upon  the  borders  of  the  Mediterranean  and 
of  the  ocean,  are  the  salicornia  europea,  the  salsola  tragus^ 
the  statice  limonium,  the  triplex  portulacoides,  the  salsola 
kali,  the  loareck,  &c.  The  soda  which  is  afforded  by  some 
of  these  is  of  a  middling  quality  :  the  richest  in  alkali  is 
the  salicornia ;  in  some  of  them  it  does  not  exist  sensibly ; 
these  abound  in  muriate  and  sulphate  of  soda  mixed  and 
strongly  (frittes)  fused  with  lime,  silica,  alumina,  and 
magnesia ;  the  soda  extracted  from  these  plants,  though 
weak,  has  nevertheless  its  use  in  the  arts ;  it  is  employed 
in  glass  works,  where,  by  means  of  the  lime  it  contains, 
and  the  charcoal  which  is  made  to  enter  into  the  composi- 
tion for  making  glass,  the  sulphate  of  soda  is  decomposed, 
and  the  salt  being  left  free  promotes  the  fusion  of  the 
earthy  substances.  When  soda  contains  10  or  12  per  cent. 
of  alkali,  it  serves  to  make  weak  leys  in  the  soap  manufac- 
tories. 

In  addition  to  the  sodia  procured  by  the  combustion  of 
marine  plants,  chymistry  furnishes  us  with  the  means  of 
supplying  it  to  commerce  by  the  decomposition  of  the  mu- 
riate of  soda  or  marine  salt ;  this  is  converted  into  a  sul- 
phate by  means  of  sulphuric  acid,  and  the  last  formed  salt 
afterward  decomposed  in  a  reverberatory  furnace,  in  which 
it  is  mixed  with  charcoal  and  chalk. 

The  soda  of  commerce  is  never  pure  ;  it  contains  at  the 
utmost  but  30  or  40  per  cent,  of  alkali :  a  solution  of 
it  evaporated,  yields  octahedral  crystals  with  rhomboi- 
dal  bases  ;  these  crystals  consist  of  alkali  and  carbonic 
acid. 


FIXED    ALKALIES.  V75 

In  order  that  soda  may  possess  all  the  requisite  strength, 
it  is  necessary  to  separate  it  from  the  carbonic  acid  with 
which  it  is  always  united,  and  by  which  its  properties  are 
weakened.  This  is  easily  done  by  mixing  quick-lime  with 
a  solution  of  soda.  The  acid  has  so  strong  an  affinity  for 
lime  as  to  quit  the  soda  to  combine  with  it.  The  ley  pro- 
cured from  this  mixture  is  caustic,  and  leaves  a  burning 
impression  upon  the  tongue  :  the  soda  thus  purified  acts 
more  readily  upon  the  bodies  with  which  it  combines. 
This  mode  of  preparation  is  indispensable  when  soda  is  to 
be  employed  with  oil  in  the  manufactory  of  hard  soap ;  it 
is  useless  when  it  is  to  be  combined  at  a  strong  heat  with 
earthy  bodies,  as  is  the  case  in  glass  works. 

Davy  discovered  soda  and  potash  to  be  metallic  oxides, 
or  burnt  metals;  and  Berzelius  has  proved  that  when 
these  two  alkalies  are  pure,  potash  is  composed  of  -^^  of 
oxygen,  and  yVu  of  potassium,  and  that  soda  was  the  result 
of  74.42  of  sodium  in  100  parts,  and  25.58  of  oxygen. 

Besides  the  substances  of  which  I  have  spoken,  plants 
contain  certain  salts,  earths,  and  metallic  oxides,  which 
have  never  been  extracted,  either  for  domestic  purposes  or 
to  be  employed  in  manufactures  :  the  existence  of  these 
is  however  so  constant,  their  proportions  so  little  varied  in 
the  same  kind  of  plant,  and  their  situations  in  the  different 
parts  of  vegetables  so  marked,  that  they  must  be  regarded 
as  belonging  essentially  to  vegetation,  and  not  as  being  in- 
troduced accidentally  and  without  design  into  the  organs 
of  the  bodies  in  which  they  are  found. 

The  most  abundant  salts  in  plants  are  the  sulphate  of 
potash,  and  common  salt,  the  phosphates  of  lime,  and  the 
nitrate  of  potash  :  the  sulphate  and  muriate  of  soda  do  not 
exist  in  any  considerable  quantity,  excepting  in  marine 
plants. 

Of  the  four  earths  procured  from  these  plants  by  com- 
bustion, the  one  most  extensively  found  is  silica ;  next  to 
that  comes  lime,  and  afterwards  magnesia  and  alumina. 

M.  Th.  de  Saussure,  in  his  highly  valuable  work  upon 
vegetation,  has  given  us  the  results  of  the  analytical  inves- 
tigations he  has  made  for  determining  the  quantity  of 
ashes,  salts,  earths,  and  metallic  oxides,  which  are  fur- 
nished by  an  equal  weight  of  a  great  variety  of  vegetables  : 
these  results  are  as  follows. 


176 


CHYMISTRY    APPLIED    TO    AGRICULTURE. 


Names  of  Plants. 

!ontained 
parts  of 
plants. 

jont^ined  • 
parts  of 
plants. 

shes  c 
nlOO 
green 

shes  c 

nlOO 

dry] 

<"^ 

<- 

1.  Leaves  of  the   oak,  {quercus  robur,)  of  the 

10th  of  May 

13 

53 

2.  The  same  of  the  27th  of  September 

24 

55 

3.  Stems  or  branches  of  young  oaks  stripped 

of  their  bark,  10th  of  May     . 

u 

4 

4.  Bark  of  the  above-mentioned  branches    .. 

(( 

60 

5.  Wood  of  the   oak    separated  from    the   al- 

burnum  

(( 

2 

6.  Alburnum  of  the  wood  above-mentioned  . 

u 

4 

7.  Bark  of  the  trunks  of  the  oaks   above-men- 

tioned     

u 

60 

8.  Liber  of  the  above-mentioned  bark  . 

u 

73 

9/  Extract  of  the  wood  of  the  above-mentioned 

oak 

u 

61 

10.  Mould  of  oak  wood 

u 

41 

11.  Extract  of  the  above  mould 

u 

111 

12.  Leaves  of  the  poplar,  {populus  nigra,)  of  the 

26th  of  May 

23 

66 

13.  Leaves  of  the  same  of  the  12th  of  September 

41 

93 

14.  Trunks  of  the  same  poplars  stripped  of  their 

bark,  September  12th    . 

(( 

8 

15.  Bark  of  the  same  trunks  .... 

u 

72 

16.  Leaves  of  the  nut  tree,  [coryllus  avellana,) 

ofthelstofMay 

u 

61 

17.  The  same  washed  with  cold  distilled  water 

u 

57 

18.  Leaves  of  the  nut  tree  of  the  22d  of  June 

28 

62 

19.  The  same  of  the  20th  of  September 

33 

70 

20.  Branches  of  the  same  tree  stripped  of  their 

bark,  1st  of  May 

« 

■  5 

21.  Bark  of  the  same  branches      . 

« 

62 

22.  Wood  of  the  Spanish  mulberry  tree,  [rmrus 

nigra,)  separated  from  the  bark,  November 

K 

7 

23.  Alburnum  of  the  same     .... 

U 

13 

24.  Bark  of  the  above  branches 

(( 

89 

25.  Liber  of  the  bark 

u 

88 

26.  Wood  of  the  yoke   elm,  [carpinus   betulus,) 

separated  from  the  alburnum 

4 

6 

27.  Alburnum  of  the  above     .... 

4 

7 

28.  Bark  of  the  same 

88 

137 

29.  Trunks,  and  branches  stripped  of  their  leaves. 

of  the   chestnut,  [(BscuLus   hippocastanumS 

10th  of  May  ...                .        . 

(( 

35 

FIXED    ALKALIES. 


177 


Water    of   vegeta- 
tion in  100  parts  of 
the  plants  when 
green. 

ll 

1 

-a 
1 

1 

1 

o 
>-. 

'2 
'x 

o 

.2 
1 
1 

i 

745 

47 

24 

0.12 

3 

0.64 

25.24 

549 

17 

18.25 

23 

14.5 

1.75 

25.5 

u 

26 

28.5 

18.25 

0.12 

1 

32.58 

u 

7 

4.5 

63.25 

0.25 

1.75 

22.75 

(( 

38.6 

4.5 

32 

2 

2.25 

20.65. 

(( 

32 

24 

11 

7.5 

2 

23.5 

({ 

7 

3 

66 

1.5 

2 

21.5 

(( 

7 

3.75 

65 

0.5 

1 

22.75 

(( 

51 

<(  u 

u  u 

t(  (( 

((  u. 

u      u 

(( 

24 

10.5 

10 

32 

14 

8.5 

(( 

66 

u      u 

U    (( 

((   u 

u      « 

((   a 

652 

36 

15 

29 

5 

1.25 

15.75 

565 

26 

7 

36 

11.5 

1.5 

18 

(( 

26 

16.75 

27 

3.3 

1.5 

24.5 

u 

6 

5^ 

60 

4 

1.5 

23.2 

u 

26 

23.3 

22 

2.5 

1.5 

24.7 

u 

8Si 

19.5 

44.1 

4 

2 

22.5 

655 

22.7 

14 

29 

11.3 

1.5 

21.5 

557 

11 

12 

36 

22 

2 

17 

(( 

24.5 

35 

8 

0.25 

0.12 

32.2 

M 

12.5 

5.5 

54 

0.25 

1.75 

26 

U 

21 

5.25 

56 

0.12 

0.25 

20.38 

U 

26 

27.25 

24 

1 

0.25 

21.5 

u 

7 

8.5 

45 

15.25 

1.12 

23.13 

u 

10 

16.5 

48 

0.12 

1 

24.38 

346 

22 

23 

26 

0.12 

2.25 

26.63 

390 

18 

36 

15 

1 

1 

29 

346 

4.5 

4.5 

59 

1.5 

0.12 

30.88 

u 

9.5 

((   u 

«  " 

((  t( 

u  u 

«  a 

178 


CHYMISTRY    APPLIED    TO    AGRICULTURE. 


30. 
31. 
32. 
33. 
34. 
35. 
36. 
37. 

38. 
39. 
40. 
41. 
42. 


43. 

44. 
45. 

46. 


47. 

48. 

49. 
50. 
51. 
52. 
53. 

54. 

55. 

56. 
57. 

58. 


Leaves  of  the  chestnut,  10th  of  May 

The  same  of  the  23d  of  July    . 

The  same  of  the  27th  of  September 

Flowers  of  the  same 

Ripe  fruits  of  the  same,  5th  of  October    . 

Pea  vines,  {pisum  sativum,)  in  flower 

The  same  bearing  ripe  seeds   . 

Plants  of  the  marsh  bean,  {vicia  fabia,)  be- 
fore flowering,  23d  of  May   . 

The  same  whilst  in  flower,  23d  of  June 

The  same  bearing  their  ripe  seeds  . 

The  same  separate  from  their  ripe  seeds 

Seeds  of  the  same 

Bean  plants  in  blossom,  raised  from  seeds  of 
the  same  kind,  and  watered  with  distilled 
water 

Golden  rod,  [solidago  vulgaris,)  before  flow- 
ering      

The  same  when  ready  to  flower,  15th  of  July 

The  same  bearing  ripe  seeds,  20th  of  Sep- 
tember   

Plants  of  the  turnsol,  {helianthus  annuus,)  of 
the  23d  of  June,  one  month  before  flow- 
ering      

The  same  when  beginning  to  flower,  23d  of 
July 

The  same  of  the  20th  of  September,  bearing 
their  ripe  seeds  .... 

Plants  of  wheat,  [triticum  sativum,)  in  flower 

The  same  bearing  ripe  seeds  . 

The  same  one  month  before  flowering    . 

The  same  when  it  flowers,  14th  of  June 

The  same  of  the  28th  of  July,  bearing  ripe 
seed      ...  ... 

Straw  of  the  above  wheat  separated  from  the 
seed . 

Kernels  selected  from  the  above  wheat   . 

Wheat  bran 

Plants  of  maize,  [zea  mms,)  of  the  23d  of  June 
one  month  before  flowering  . 

The  same  of  July  23d,  in  flower 


16 
29 
31 
9 
12 


16 
20 


13 
23 


16 


FIXED    ALKALIES. 


179 


•2 

1 

1 

S 

Water    of   vej 
tion  in  100  par 
the  plants  wl 
green. 

1 

% 
1 

>. 

1 

.2 

1 

^ 

782 

50 

U        (( 

u     u 

u     u 

u     u 

U        ii 

652 

24 

u     u 

u     u 

«     u 

u     u 

U       ii 

636 

13.5 

u     u 

u     u 

u     u 

it      ti 

U       it 

873 

50 

w      « 

a     u 

u     a 

u     u 

it     ii 

647 

75 

10.5 

u     u 

0.75 

0.5 

13.25 

(( 

49.8 

17.25 

6 

2.3 

1 

24.65 

u 

34.25 

22 

14 

11 

2^ 

17.25 

895 

55.5 

14.5 

a5 

1.5 

0.5 

24.50 

876 

55.5 

13.5 

4.12 

1.5 

0.5 

24.38 

u 

50 

17.75 

4 

1.75 

0.5 

26 

(( 

42 

5.75 

36 

1.75 

1 

12.9 

u 

69.28 

27.92 

((    (( 

u     u 

0.5 

2.3 

(( 

60.1 

30 

tt     u 

u     u 

0.5 

9.4 

(( 

67.5 

10.75 

1.5 

1.5 

0.75 

18.25 

a 

59 

8.5 

9.25 

1.5 

0.75 

21 

u 

48 

11 

,  17^ 

3.5 

1.5 

18.75 

u 

63 

6.7 

11.56 

1.5 

0.12 

16.67 

877 

61 

6 

12.5 

1.5 

0.12 

18.78 

753 

51.5 

22.5 

4 

3.75 

0.5 

17.75 

(( 

43J25 

12.75 

0.25 

32 

0.5 

12.25 

t  « 

11 

15 

0.25 

54 

1 

18.75 

(( 

60 

11.5 

0.25 

12.5 

0.25 

15.5 

699 

41 

10.75 

0.25 

96 

0^ 

21.5 

u 

10 

11.75 

0.25 

51 

0.75 

23 

u 

22.5 

6J2 

1 

61.5 

1 

78 

u 

47.16 

44.5 

u     u 

0.5 

0.25 

7.6 

u 

4.16 

46^ 

u     u 

0.5 

055 

8.6 

u 

69 

5.75 

0.25 

7.5 

0.25 

17 

u 

69 

6 

0.25 

7.5 

0.25 

17 

180 


CHYMISTRY   APPLIED   TO   AGRICULTURE. 


Names  of  Plants. 

Ashes  contained 
in  100  parts  of 
green  plants. 

Ashes  contained 

in  100  parts  of 

dry  plants. 

59.  Plants  of  maize  bearing  ripe  grain  . 

60.  Stalks  of  the  same  separated  from  their  ripe 

ears 

61.  Ears  of  tlie  above  stalks  .... 

62.  Kernels  of  the  above  maize    . 

63.  Straw  of  barley,  {hordeum  vvlgare^)  separated 

from  its  ripe  seeds         .... 

64.  Grains  of  barley  from  the  above  straw     . 

65.  Grain  of  barley 

66.  Oats 

67.  Leaves  of  the  TOBe-bBLy,  {rhododendrum  ferru- 

gineum,)  growing  upon  Jura,  a  calcareous 
mountain,  June  20th 

68.  The  same  growing  upon  Breven,  a  granitic 

mountain,  27th  of  June 

69.  Stalks  and  branches  of  the  rose-bay  growing 

upon  Jura,  20th  of  June 

70.  Stems  of  the  rose-bay  from  Breven,  27th  of 

June 

71.  Leaves  of  the  pine,  {pinus  ahieSf)  growing 

upon  Jura,  June  20th    .... 

72.  The  same  growing  upon  Breven,  June  27th 

73.  Branches  of  the  pine  stripped  of  leaves,  June 

20th 

74.  A  variety  of  whortieberry,  {vaccinium  myr- 

tUlvSf)  growing  upon  Jura,  August  29th 

75.  The  same  growmg  upon  Breven,  August  20th 

(( 

(( 
u 
u 

u 
u 
u 
u 

u 

u 

u 

u 

u 
u 

u 

u 

u 

46 

84 
16 
10 

42 

18 

« 

31 

30 
25 

8 

8 

29 
29 

15 

26 
22 

FIXED   ALKALIES. 


181 


Water    of  vegeta- 
tion in  100  parts  of 
the  plants  when 
1           green. 

II 

CO   S 

1 

1 

1 

CQ 

o 

i 

J 

« 

((       « 

u     u 

U       tt 

((       u 

u     u 

u      u 

ti 

72.45 

li       u 

5 

U        (( 

1 

((     (( 

18 

a     u 

0.5 

3.5     ! 

it       u       . 

u 

62 

36 

<(      (( 

1 

0.12 

0.88   • 

u 

« 
u 

20 
29 
22 

1 

7.75 
32.5 
22 
24 

12.5 

it    it 

u     u 
u     u 

57 

35.5 

21 

60 

0.5 
0.25 
0.12 
0.25 

2.25 

2.8 
29.88 
14.75 

tt 

23 

14 

43.25 

0.75 

3.25 

15.63 

ii 

21.1 

16.75 

16.75 

2 

5.77 

31.52 

u 

22.5 

10 

39 

05 

5.4 

22.48 

it 

24 

11.5 

29 

1 

11 

24.5 

u 

16 
15 

12.27 
12 

43.5 
29 

2.5 
19 

1.6 
5.5 

24.13 
19.5 

u 

15 

U        li 

((       u 

11       u 

U       it 

it       u 

u 

17 

18 
22 

42 
22 

1.5 
5 

3.12 
9.5 

19.38 
17.5 

16 


182  CHYMISTRY   APPLIED    TO    AGRTCULTURE-. 


CHAPTER  X. 

»N   THE    PRESERVATION    OP   ANIMAL^  AND   VEGETABLE 

SUBSTANCES, 

Each  product  of  agriculture  has  its  season ;  there  are 
few  which  the  earth  yields  at  all  times.  From  this  well- 
known  truth  there  result  two  incontestable  facts ;  the  first 
of  these  is,  that  in  the  years  of  abundance  the  production 
is  greater  than  the  consumption,  and  consequently  a  part 
is  lost,  and  the  remainder  sold  at  a  low  price ;  the  second  is, 
that  the  consumption  of  the  greater  part  of  the  articles  of 
agricultural  produce  takes  place  within  one  year,  whilst,  if 
the  agriculturist  had  sure  means  of  preserving  them,  it 
might  be  prolonged  indefinitely,  and  thus  the  sale  of  them 
rendered  more  profitable.  The  question  of  the  best  man- 
ner in  which  the  productions  of  the  earth  may  be  pre- 
served^ is  then  one  of  the  most  important  to  be  solved  ii» 
rural  economy. 

Before  making  known  the  processes  by  which,  as  we 
have  learned  from  experience,  agricultural  products  may  be 
preserved  free  from  change,  it  is  necessary  to  cast  a  glance 
upon  the  causes  by  which  that  change  is  produced. 

The  natures  of  all  bodies  which  have  ceased  to  live  or 
vegetate  are  changed,  as  soon  as  the  physical  or  chymical 
laws  by  which  they  were  governed,  cease  to  act ;  the  ele- 
ments of  vrhich  they  were  composed  then  form  new  com- 
binations, and  consequently  new  substances. 

Whilst  an  animal  lives,  or  a  plant  vegetates,  the  laws  of 
chymical  affinity  are  continually  modified  in  its  organs  by 
the  laws  of  vitality  ;  but  when  the  animal  or  plant  ceases 
to  live,  it  becomes  entirely  subject  to  the  laws  of  chymical 
affinity,  by  which  alone  its  decomposition  is  effected. 

The  principles  of  the  atmospheric  air  which  is  imbibed 
by  the  organs  of  living  bodies,  whether  animal  or  vegeta- 
ble, are  decomposed  and  assimilated  by  them,  whilst  dead 
bodies  are  decomposed  by  its  action.  Heat  is  the  most 
powerful  stimulant  of  the  vital  functions,  yet  it  becomes 
sfler  death  one  of  the  most  active  agents  in  the  work  of 
destru<5tion.  Our  effijrts,  then,  for  the  preservation  of 
bodies  ought  to  be  directed  to  counteracting  or  governing 
those  chymical  or  physical  agents,  from  the  action  of  which 
they  su-ffer ;  and  we  shall  see  that  all  the  methods  whicb 


PRESERVATION  OF  FRriTS  BT  DRYING-        183 

liavB  been  successful,  are  those  which  have  been  formed 
upon  this  principle. 

The  chymicaJ  agents,  which  exert  the  most  powerful  in- 
fluence over  the  products  of  the  earth,  are  air,  water,  and 
heat ;  the  action  of  these,  however,  is  not  equally  powerful 
over  all  classes  of  plants;  the  soft  and  watery,  and  those 
which  approach  the  nearest  to  animal  matter,  decompose 
most  readily  ;  the  principles  of  such  are  less  coherent,  less 
strongly  united  than* of  others;  so  that  the  action  of  disor- 
ganizing agents  upon  them  is  prompt  and  effectual. 

All  the  methods  now  employed  for  the  preservation  of 
bodies,  consist  in  so  far  changing  their  nature,  as  to  de- 
prive them  of  the  elements  of  destruction  contained  with- 
in their  own  organs ;  or  in  secluding  the  substances  to  be 
preserved  from  contact  with  the  destructive  agents  men- 
tioned in  the  preceding  paragraph  ;  or  in  causing  them  to 
imbibe  certain  other  substances,  the  anti-putrescent  quali- 
ties of  which  counteract  all  action,  whether  of  internal 
or  external  agents. 


ARTICLE    L 


On   the   Preservation   of  the  Fruits   of  the   Earth    hy 
Drying. 

In  all  vegetable  products,  water  exists  in  two  different 
states,  one  part  of  it  being  found  free,  and  the  other  in  a 
state  of  true  combination :  the  first  portion,  not  being 
confined  except  by  the  covering  of  fhe  vegetable,  evapor- 
ates at  the  temperature  of  the  atmosphere ;  the  second  is 
set  free  only  at  a  temperature  sufficiently  high  to  decom- 
pose the  substances  containing  it :  the  first,  though  for- 
eign to  the  composition  of  the  vegetable,  enters  into  every 
part  of  it,  dissolving  some  of  its  principles,  serving  as  a 
vehicle  for  air  and  heat,  and  being  converted  by  cold  into 
ice ;  by  these  several  properties  it  greatly  facilitates  de- 
composition :  the  second  portion,  from  which  no  evil  of 
the  kind  arises,  is  found  combined  and  solidified  in  the 
plants,  and  its  action  is  thus  neutralized.  Drying,  then, 
consists  in  depriving  the  product  to  be  preserved  of  the 
»^ater  contained  in  it  in  a  free  state,  by  heat ;  and  from 


184  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

what  has  been  observed  above,  it  follows,  that  too  great  a 
degree  of  heat  must  not  be  applied,  as,  in  consequence, 
the  taste  and  the  organization  of  the  substance  would  be 
changed  by  a  commencement  of  the  decomposition  of  its 
constituent  principles :  the  temperature  should  never  be 
higher  than  from  35°  to  45°  of  the  centigrade.  (=  from 
95°  to  113°  Fahrenheit.) 

Drying  can  be  performed  either  by  the  heat  of  the  sun 
or  in  stove  rooms.  In  the  southern  climates  the  heat  of 
the  sun  is  sufficiently  powerful  to  dry  the  greater  part  of 
the  fruits,  and  thus  to  preserve  them  unaltered  :  the  dry- 
ing is  effected  by  exposing  them  to  the  rays  of  the  sun 
upon  hurdles  or  slates,  where  they  will  be  protected  from 
rain,  dust,  and  injury  from  animals.  Practice  alone  is 
sufficient  to  enable  one  to  judge  of  the  degree,  to  which 
each  kind  of  fruit  must  be  dried  in  order  to  its  preser- 
vation. 

When  the  outer  skin  or  rind  of  the  fruit  is  of  a  kind  to 
prevent  the  water  from  passing  off  freely,  incisions  are 
made  in  the  rind  to  facilitate  its  evaporation.  In  this 
manner  are  prepared  most  of  the  dried  fruits,  which  form 
so  considerable  an  article  of  commerce  between  the  south 
and  north. 

Those  fruits  which  contain  much  sugar,  as  prunes,  figs, 
musk  grapes,  &lc.,  may  be  prepared  in  the  above  manner, 
and  preserve  nearly  all  their  qualities,  but  the  acid  fruits 
acquire  a  disagreeable  sharp  taste  by  the  concentration  of 
the  juices ;  some  of  them,  however,  may  be  kept  advanta- 
geously in  this  way. 

In  the  hottest  countries  the  process  of  drying  is  often 
commenced  by  subjecting  the  fruits  to  the  heat  of  an  oven, 
after  which  they  are  exposed  to  the  sun ;  some  kinds  of 
fruits  are  thrown  into  a  weak  ley,  till  their  surface  becomes 
wrinkled,  when  they  are  taken  out,  carefully  washed  in  cold 
water,  and  afterwards  dried  in  the  sun  :  cherries  particular- 
ly are  treated  in  this  manner.  When  the  heat  of  the  sun  is 
not  sufficiently  great  to  evaporate  all  the  water  contained  in 
the  pulp  of  large,  fleshy  fruits,  they  may  be  cut  in  pieces 
and  then  dried ;  in  this  manner  apples  and  pears  are  pre- 
pared for  keeping.* 

But  this  method  is  neither  speedy  nor  economical  enough 

[  *  In  this  country,  apples,  pumpkins,  squashes,  and  peaches  are 
kept  by  drying. — Tr.] 


PRESERVATION  OF  FRUITS  BY  DRYING.       185 

for  such  preparations  as  have  but  little  value  in  commerce, 
and  which  can  never  supply,  for  domestic  purposes,  tlie 
place  of  those  whole  fruits,  which  may  be  easily  preserved 
from  one  season  to  another :  it  is  therefore  customary  to 
perform  the  drying  either  in  stove  rooms  or  ovens.  In  the 
first  case,  the  fruits,  after  being  cut,  are  placed  upon  hur- 
dles arranged  in  rows  in  a  chamber  heated  to  1 12°  :  in 
the  second,  the  fruits  are  put  into  an  oven,  from  which 
bread  has  just  been  drawn ;  this  is  repeated  if  the  fruits 
be  not  sufficiently  dried  the  first  time. 

Some  of  the  fruits  referred  to  above,  may  be  dried 
without  being  cut:  of  this  kind  are  the  tender  pears, 
which  cannot  be  preserved  fresh  through  the  winter ;  such 
us  the  rousselet,  the  butter  pear,  the  doyenne,  the  mes- 
sire-jean,  the  martinsec,  &lc.  These  are  first  peeled,  and 
then  thrown  into  boiling  water,  after  which  they  are  put 
upon  hurdles  into  an  oven  heated  less  than  is  required  for 
bread ;  after  an  interval  of  three  or  four  days  the  pears 
are  again  exposed  to  the  same  degree  of  heat,  having  been, 
however,  first  flattened  between  the  palms  of  the  hands ; 
whence  they  have  acquired  the  name  of  pressed  pears. 

Fruits  prepared  in  either  of  the  above  ways  are  suscep- 
tible of  fermentation  upon  being  soaked  in  water,  and 
they  thus  serve  to  make  a  cheap  and  useful  drink. 

In  those  countries  where  these  fruits  abound,  the  dry- 
ing of  them  is  commenced  about  the  1st  of  August,  and 
those  are  made  use  of,  which  then  fall  from  the  trees ;  in 
autumn,  when  the  harvest  is  gathered  in,  the  soundest 
and  finest  fruits  are  carefully  selected  to  be  used  fresh, 
whilst  the  rest  are  dried  and  preserved  in  a  place  free 
from  moisture,  to  be  employed  in  making  drinks.  I  shall 
in  another  chapter  speak  of  the  processes  by  which  this  is 
effected. 

The  herbage,  which  serves  as  food  for  domestic  animals, 
can  be  preserved  only  by  drying,  and  this  in  all  countries 
is  practised  at  the  time  of  cutting.  Fodder,  which  is  im- 
prudently stacked  up  whilst  still  damp,  ferments,  and  th« 
heat  thus  produced  is  sufficient  to  change  the  quality,  pro- 
duce mouldiness,  and  is  sometimes  even  great  enough  to 
set  the  whole  on  fire. 

There  are  some  fruits,  which  may,  by  a  few  slight  pre- 
cautions, be  preserved  throughout  the  year.  The  first  of 
these  precautions  is,  that  of  depriving  their  surface  of 
all  moisture  before  putting  them  up ;  and  the  second  conr 
16* 


186  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

gists  in  keeping  them  in  dry  places,  where  the  temperature 
will  constantly  be  between  50°  and  54°  Fahrenheit ;  the 
third,  in  separating  the  fruits,  so  that  they  shall  not  come 
in  contact;  I  have  seen  apples  preserved  in  this  manner 
eighteen  months.  It  is  necessary  to  be  particular  in  select-r 
ing  fruit  for  preservation ;  that  only  should  be  taken  which 
is  perfectly  sound. 

Wood  and  other  portions  of  vegetables,  and  various  ani- 
mal substances,  are  likewise  preserved  by  drying ;  .this  pro- 
cess increases  their  hardness  and  renders  them  less  accessi- 
ble to  the  action  of  air,  insects,  and  other  destructive  agents. 

The  process  of  drying  is  not  confined  to  preserving 
fruits  from  decomposition :  it  furnishes  the  means  of  secur- 
ing their  juices  unaltered  for  the  formation  of  extracts, of 
them. 

When  the  juices  of  plants  can  be  extracted  by  pressure 
alone,  it  is  only  mftcessary  to  evaporate  these  juices  at  a  due 
degree  of  heat  and  in  suitable  vessels,  till,  being  deprived 
of  all  the  water  which  retained  them  in  a  liquid  state,  they 
are  reduced  to  dryness.  Evaporation,  if  continued  for  a 
long  time  at  the  temperature  of  boiling  water,  changes  these 
juices  a  little ;  the  albumen,  which  is  contained  more  or 
less  abundantly  in  all  sweet  fruits,  is  coagulated,  and  after 
this  they  are  no  longer  susceptible  of  undergoing  the  vinous 
fermentation. 

The  must  of  grapes,  operated  upon  in  this  manner,  fur- 
nishes an  extract  called  raisine,  which  is  an  article  of 
food  both  wholesome  and  agreeable,  and  which,  when 
soaked  in  water,  decays  without  producing  alcohol.  The 
fermentative  power  of  this  substance  may,  however,  be  re- 
stored by  mixing  with  it  a  little  of  the  yeast  of  beer,  as 
this  repairs  the  loss,  which  the  juices  had  sustained  by 
heat  during  evaporation. 

All  the  juices  obtained  from  sweet  fruits  may  be  convert- 
ed into  extracts,  and  thus  furnish  agreeable  food  :  the  qual- 
ity of  the  extract  varies  according  to  the  quantity  of  sugar 
contained  in  the  fruit,  and  the  care  taken  in  the  operation : 
when  the  juices  are  several  times  clarified,  and  evaporation 
carried  on  in  a  water  bath,  care  being  taken  to  stir  the 
liquid  to  prev'ent  its  adhering  to  the  sides,  the  color  and  taste 
of  the  extract  or  jelly  obtained  is  far  superior  to  that  pro- 
cured without  employing  these  precautions. 

The  sweetest  fruits,  however,  even  the  well  ripened 
grapes   of  the    south,    contain   a  portion  of  acid,  which, 


PRESERVATION  OF  FRUITS  BY  DRYING.       187 

when  concentrated  by  evaporation,  acts  upon  the  copper 
boilers  in  which  the  operation  is  carried  on,  so  as  to  form 
an  acetate  of  copper  :  this,  by  producing  colics,  would 
render  the  use  of  thq  extract  dangerous,  especially  at  the 
south,  where  the  principal  article  of  food  for  children  is 
the  raisine.  In  order  to  obviate  this  serious  evil,  an  an- 
cient and  generally  followed  custom  is  observed :  as  soon 
as  the  must  of  the  grapes  begins  to  boil  in  the  coppers,  a 
bunch  of  keys  is  thrown  in,  and  allowed  to  remain  till  the 
operation  is  completed :  these  keys  attract  the  copper  and 
become  covered  with  the  precipitate  thus  formed,  and 
nothing  remains  in  the  extract  but  the  acetate  of  iron, 
which  is  not  injurious. 

I  have  observed  that  the  juices  of  all  succulent  fruits 
might  be  converted  into  extracts,  and  thus  preserved  for 
use  in  the  course  of  the  year;  but  the  greater  part  of 
these  juices,  when  concentrated  by  evaporation,  are  so 
excessively  acid  as  to  be  totally  unfit  for  food,  and  they 
only  form,  when  mixed  with  water,  a  very  sour  drink.  In 
order  to  correct  or  conceal  this  acidity,  these  juices  are 
boiled  with  an  equal  weight  of  sugar,  and  thus  made  into 
sirups  and  jellies. 

As  it  is  of  importance  to  be  able  to  extract  and  preserve 
for  domestic  purposes,  for  pharmacy,  and  for  the  arts,  cer- 
tain vegetable  products,  which  can  be  only  very  imper- 
fectly obtained  by  mechanical  pressure,  recourse  is  had  to 
other  means ;  those  liquids  are  made  use  of  which  will 
dissolve  the  wished  for  principles,  and  the  solution  is 
afterwards  evaporated  to  dryness. 

The  fluid  most  generally  employed  for  solutions  is  wa- 
ter; this  dissolves  the  extractive  matter,  mucilage,  sugar, 
and  the  greater  part  of  the  salts,  and  mixes  with  the 
mealy  portions  of  plants ;  it  may  be  applied  cold  or  hot  to 
the  vegetables,  or  they  may  be  boiled  in  it,  according 
to  the  nature  of  the  principle  to  be  extracted ;  water  will 
dissolve  all  that  is  soluble  in  them,  and  the  extracts  may  be 
obtained  from  the  solution  by  evaporation. 

The  resins,  which  are  found  so  abundantly  in  some 
vegetables,  are  not  soluble  in  water,  and  the  place  of  this 
liquid  must  be  supplied  by  alcohol,  in  which  the  plant  must 
be  digested ;  evaporation  will  separate  the  alcohol  from  the 
resin  which  it  holds  in  solution.  In  order  to  avoid  the  ac- 
cidents that  might  occur  from  the  dispersion  in  the  at- 
mosphere  of  a   very   inflammable  vapor,  the  evaporation 


188  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

must  be  so  conducted  that  the  dissolvent  may  be  received 
into  an  alembic  or  close  vessel. 

In  addition  to  the  methods  of  preserving  fruits  by  drying, 
and  by  reducing  their  juices  to  the  state  of  sirups  and  jellies 
by  natural  or  artificial  heat,  M.  de  Montgolfin  has  applied 
the  action  of  the  air  pump  with  great  success.  I  have  tast- 
ed juices  prepared  and  thickened  in  this  manner,  and  I 
thought  they  were  much  superior  to  those  that  had  been 
evaporated  in  either  of  the  modes  hitherto  usually  practised. 
I  do  not  doubt  that,  when  this  method  becomes  better  known, 
it  will  be  generally  adopted. 


ARTICLE    II. 

On  the    Preservation  of  the  Fruits  of  the  Earth    hy  Se- 
cluding them  from  the  Action  of  Air,  Water,  and  Heat. 

The  atmospheric  air  coming  in  contact  with  fruits  de- 
prives them  of  their  carbon,  and  forms  carbonic  acid. 

Fruits  exposed  to  the  solvent  action  of  water  suffer  decom- 
position by  having  the  affinity  existing  between  their  con- 
stituent principles  weakened,  and  at  length  destroyed. 

Heat  dilates  the  particles  of  bodies,  and  thus  diminishes 
the  forces  of  cohesion  and  attraction,  and  favors  the  admis- 
sion of  air  and  water. 

The  combined  action  of  these  three  agents  produces 
very  speedy  decomposition ;  the  effect  produced  by  any 
one  of  them  is  slower,  and  the  results  different.  So  that 
in  order  to  preserve  fruits  from  decomposition  it  is  neces- 
sary to  guard  them  from  the  power  of  these  three  de- 
stroyers. 

In  several  European  countries,  particularly  in  the  north, 
roots  of  all  kinds  are  preserved  merely  by  secluding  them 
entirely  from  air,  heat  and  water ;  this  is  done  by  digging 
deep  ditches  in  a  dry  soil  upon  a  spot  a  little  elevated,  and 
depositing  in  them  the  roots,  which  are  afterwards  cov- 
ered over  with  a  layer  of  earth,  of  sufficient  thickness  to 
prevent  them  from  suffering  by  the  frost;  over  the  whole 
is  then  laid  a  bed  of  straw,  broom,  or  fern,  in  order  to  pro- 
tect them  from  rain  and  from  the  water  of  melting  snows 
which  might  filtrate  through  into  the  pit. 


PRESERVATION    OF    FRUITS    BY    SECLUSION.  189 

Roots,  to  keep  well,  must  have  their  surfaces  entirely  free 
from  moisture  before  being  thus  buried. 

The  roots  have  in  themselves  a  preserving  principle,  which 
does  not  exist  in  a  dead  plant  or  one  that  has  terminated 
its  period  of  vegetation  :  they  have  as  yet  lived  but  a  por- 
tion of  their  vegetable  life ;  they  have  not  formed  the  seeds, 
which  secure  the  continuance  of  their  species ;  and  to  fulfil 
this  great  design  of  nature  they  profit  by  every  circumstance, 
which  can  favor  and  confirm  their  vegetation;  but  when 
placed  for  a  time  beyond  the  action  of  air,  water,  and  heat, 
their  organs  remain  at  rest  till  again  excited  by  the  presence 
of  these  powerful  agents. 

As  dead  bodies  do  not  retain  this  animating  principle, 
the  energies  of  which  are  only  suspended  in  roots,  grains, 
&/C.  during  the  winter,  so  they  suffer  decomposition, 
though  less  rapidly,  from  the  contact  of  air,  heat,  and 
water. 

In  the  way  of  which  I  have  just  spoken,  beets,  carrots, 
potatoes,  and  many  other  vegetables  may  be  preserved  unin- 
jured till  summer. 

A  very  simple  method  of  preserving  them  at  least  free 
from  decomposition,  is,  to  heap  them  up  in  piles  upon  a  very 
dry  soil,  and  then  to  cover  them  upon  all  sides  with  straw 
enough  to  protect  them  from  rain  and  frost :  in  England  this 
is  esteemed  the  best  method  of  keeping  turnips. 

Vegetables  may  likewise  be  preserved  by  heaping  them 
up  in  barns  to  the  height  of  five  or  six  feet,  care  being  taken 
to  cover  them  well  with  straw  or  hay  at  the  commencement 
of  the  severe  cold  weather.  Should  the  roots  in  these  heaps 
begin  to  vegetate,  they  must  be  removed,  and  thus  their 
farther  developement  checked. 

Thomas  Dallas  has  published  some  very  important  ob- 
servations *  upon  the  modes  of  treating  potatoes  which  have 
been  affected  by  the  frost.  With  us  such  potatoes  are  re- 
jected, as  being  unfit  either  for  food  or  for  furnishing 
fecula.  The  able  agriculturist  above  mentioned  considers 
them  in  three  different  states ;  1  st,  when  they  are  slightly 
touched  by  the  frost ;  2d,  when  the  outer  portion  of  their 
substance  is  frozen ;  and  3d,  when  they  are  frozen  through- 
out. 

In  the  first  case  he  finds  that  nothing  more  is  necessary, 
than  to  sprinkle  the  roots  with  lime  to  absorb  the  water  form- 

*  Biblioth^que  Universelle,  Art.  Agriculture.    Vol.  II.  p.  123. 


190  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

ed  under  the  skin,  which  would  speedily  occasion  their  com- 
plete decomposition.  In  the  second  instance  he  causes  the 
potatoes  to  be  pared  and  thrown  for  some  hours  into  water 
slightly  salted.  When  the  potatoes  are  completely  frozen, 
he  finds  them  to  yield,  upon  distillation,  a  spirituous  liquor 
resembling  the  best  rum,  and  affording  much  more  alcohol, 
and  that  of  a  better  quality,  than  can  be  procured  from  the 
roots  before  freezing. 

The  preservation  of  grains  has  always  been  an  object 
of  much  consideration  both  to  governments  and  agricultur- 
ists, and  it  is  a  peculiarly  interesting  one,  because  bread 
forms  so  large  a  portion  of  the  nourishment  of  Europeans, 
and  because  the  scarcity  and  high  price  of  it  have  been 
the  cause  or  the  pretext  for  popular  discontents  and  insur- 
rections. 

The  art  of  preserving  grains  unchanged,  besides  obviating 
this  evil,  presents  the  additional  advantage  to  the  agricultur- 
ist of  enabling  him  to  make  a  good  harvest  compensate  for 
a  bad  one,  by  maintaining  the  price  of  bread  stuff  at  a  rate 
suitable  alike  for  the  consumer  and  the  producer ;  and  thus 
avoiding  those  periodical  successions  of  high  and  low  prices, 
of  abundance  or  scarcity,  which  disturb  social  order,  and 
give  rise  to  excesses  prejudicial  to  all. 

It  appears  that  the  people  of  the  most  ancient  times  pre- 
served their  grains  uninjured  through  several  years,  mere- 
ly by  secluding  them  entirely  from  the  action  of  air  and 
moisture. 

The  Chinese  have  from  time  immemorial  preserved  their 
grains  in  pits,  which  they  call  teon :  these  ditches  are 
either  hewn  out  in  rocks  free  from  chinks  and  humidity, 
or  what  is  still  better,  they  are  dug  in  a  firm,  dry  soil.  If 
there  be  any  danger  of  humidity  about  the  pits,  they  are 
lined  with  straw,  or  wood  is  burned  in  them  to  harden  and 
dry  the  earth.  The  grain  is  not  put  into  the  pits  till  some 
months  after  the  harvest,  nor  till  it  has  been  well  dried  in 
the  sun  ;  it  is  then  covered  over  with  mats  made  of  the 
chaff  of  the  grain  or  of  straw,  and  this  again  by  a  bed  of 
earth  well  beaten  down,  that  it  may  not  be  penetrated  by 
water. 

Varro,  Columella,  and  Pliny  inform  us,  that  the  an- 
cients preserved  their  grain  in  ditches  hollowed  out  of 
rocks  or  dug  in  the  earth,  the  sides  of  them  being  lined 
with  straw,  duintus  Curtius  relates,  that  the  army  of 
Alexander  experienced  great  privation  upon  the  banks  of 


PRESERVATION   OP   FRUITS    BY   SECLUSION.  191 

the  Oxus,  because  the  inhabitants  of  the  country  preserved 
their  corn  in  subterranean  pits,  the  situation  of  which  was 
known  only  to  those  who  dug  them.* 

I  have  several  times  had  occasion  to  visit  in  Amboise 
what  are  called  Ccesar's  granaries,  and  from  examining 
the  place,  I  think  there  can  be  no  doubt  that  it  was  intend- 
ed for  the  preservation  of  grain.  About  thirty  feet  above 
the  level  of  the  waters  of  the  Loire,  there  are  dug  in  a  dry 
and  solid  calcareous  rock,  deep  and  broad  excavations  ar- 
ranged in  three  stages  separated  from  each  other  by  vaults. 
Behind  the  first  excavations,  there  are  formed  others,  and 
separated  from  them  by  a  wall  of  rock  six  or  seven  feet 
thick,  and  within  these  are  built,  of  brick  and  mortar,  cir- 
cular granaries  of  about  fifteen  feet  in  diameter  :  the  up- 
per part  of  the  granaries  is  contracted,  and  the  aperture, 
which  is  that  by  which  they  are  filled,  is  covered  over  by 
a  stone :  the  grain  is  taken  from  them  through  a  hopper 
placed  at  the  bottom.  To  avoid  all  dampness,  the  space 
contained  between  the  walls  of  the  granaries  and  those  of 
the  rock  is  filled  with  fine  and  very  dry  sand  from  the 
Loire.  A  gallery  formed  also  in  the  rock  communicates 
on  one  side  with  the  granaries,  and  on  the  other  with  a 
staircase  cut  in  the  rock,  which  conducts  directly  to  the 
banks  of  the  river.  It  would  seem  that  the  excavations 
served  as  magazines  of  stores  for  daily  consumption,  and 
the  granaries  for  reserved  supplies.  It  is  difficult  to  con- 
ceive of  any  arrangement  more  suitable  for  preserving 
grain,  or  of  a  situation  more  favorable  for  obtaining  or  for 
transporting  it. 

In  some  warm  and  dry  countries,  it  has  been  customary 
from  time  immemorial  to  preserve  grain,  with  less  pre- 
caution certainly  than  in  the  granaries  above  described, 
but  in  situations  where  it  could  be  kept  for  six  or  seven 
years.  Prosper  Alpinus  relates,  that  not  far  from  Cairo 
there  was  a  high  wall  built,  enclosing  a  spot  of  ground  of 
about  two  miles  in  circumference,  which  was  filled  every 
six  or  seven  years  with  heaps  of  wheat :  he  adds,  that  the 
abundant  dews  of  night  softened  the  outer  portions  of  the 
grain  and  caused  it  to  germinate,  but  that  in  a  short  time 
the  sun  dried  the  young  shoots,  which  then  formed  a  hard 
covering   to  the   mass,   and   did   not  permit   either  air  or 

*  Des  Fosses  propres  a  la  Conservation  des  Grains  ;  par  M.  le  comte 
de  Lasteyrie. 


192  CHYMISTRY   APPLIED    TO    AGRICULTURE. 

moisture  to  penetrate  it.  In  a  similar  manner  individuals 
may  preserve  their  grain  upon  floors  in  the  open  air,  merely 
by  covering  the  heaps  of  it  with  mats. 

In  the  Basilicata,  according  to  the  report  of  Intieri,*  the 
farmers  form  their  corn  into  heaps  upon  the  borders  of  the 
sea ;  these  are  soon  covered,  in  consequence  of  the  rains, 
with  a  strong  vegetation,  which  forms  over  them  a  layer  im- 
permeable by  air  or  water. 

There  is  a  curious  account  given  by  Joinville,  of  the  man- 
ner in  which  supplies  of  provisions  for  the  army  which  St. 
Louis  conducted  in  person  to  Jerusalem,  were  secured. 

"  Quant  nous  venimes  en  Cypre,  le  Roy  estoit  ja  en  Cypre, 
et  trouvames  grant  foison  de  la  pourveance  le  Roy ;  c'est  a 
savoir,  les  celiers  le  Roy  et  les  deniers  et  les  garniers.  Les 
celiers  le  Roy  estoient  tiex,  que  sa  gent  avoient  fait  en  mi 
les  champs  sur  la  rive  de  la  mer,  gran  moyes  de  tonniaus 
de  vin,  que  il  avoient  achete  de  deux  ans  devant  que 
le  Roy  venist,  et  les  avoient  mis  les  uns  sus  les  autres, 
et  que  quant  Ten  les  veoit  devant,  il  sembloit  que  ce  feussent 
granches.  Les  fourmens  et  les  orges  il  les  r^ avoient  mis  par 
monciaus  en  mi  les  champs ;  et  quant  en  les  veoit,  il  sem- 
bloit que  ce  feussent  montaignes  ;  car  la  pluie  qui  avoit  batu 
les  blez  de  lone  temps,  les  avoit  fait  germer  par  desus,  si  que 
il  n'i  paroit  que  I'erbe  vert. 

"  Or  avint  ainsi  que  quant  en  les  vot  mener  en  Egypte,  Ten 
abati  les  crotes  de  desus  a  tout  I'erbe  vert,  et  trouva  Ten  le 
fourment  et  I'orge  aussi  frez  comme  Ten  I'eust  maintenant 
batu."  f 

This  method  of  preservation  is  undoubtedly  less  costly 
than  that  of  digging  ditches ;  but  there  is  in  it  some  loss  of 

*  Delia  perfetta  Conservazione  del  Grano  ;  4 to.  page  12. 

t  "  When  we  came  to  Cyprus,  the  king  was  already  there,  and  we 
found  great  abundance  of  stores  collected  by  him  ;  the  cellars  of  the 
king  and  his  treasures  and  granaries  were  as  follows.  The  cellars  of 
the  king,  which  his  people  had  made  in  the  midst  of  the  fields  upon  the 
borders  of  the  sea,  were  three  in  number,  stocked  with  great  casks  of 
wine,  bought  two  years  before  the  king's  arrival ;  the  cellars  were 
placed  one  over  the  other,  so  that  when  viewed  in  front  they  looked 
like  barns.  The  wheat  and  the  barley  they  had  put  in  heaps  in  the 
midst  of  the  fields,  and  these  appeared  like  mountains,  for  the  rain  had 
moistened  the  corn  for  a  long  time,  and  caused  it  to  germinate  on  the 
outside,  so  that  nothing  was  seen  but  the  green  herb. 

"  Now  when  we  had  determined  to  carry  the  grain  into  Egypt,  and 
the  outer  crust  was  removed  from  the  heaps  of  grain,  the  wheat  and 
barley  were  found  as  fresh  as  if  but  now  piled  up." 

History  of  St.  Louis.     Paris.  1761.  folio,  pp.  28  and  29. 


PRESERVATION    OF    FRUITS    BY    SECLUSION.  193 

grain,  nor  can  the  rest  be  so  securely  kept  for  several  years 
as  it  would  be  in  pits.  The  custom  however  has  long  pre- 
vailed, and  is  still  to  be  found  throughout  Europe,  and 
even  in  Asia  and  Africa. 

The  grains  which  are  consumed  in  Algiers  and  Tunis, 
or  which  are  exported  thence,  are,  after  having  been  well 
dried  in  the  sun,  deposited  in  trenches  cut  in  the  rocks, 
and  having  their  sides  lined  with  straw.  The  Count  of 
Lasteyrie  has  found  the  same  mode  followed  in  Malta, 
Sicily,  Spain,  and  Italy.  There  are  even  some  countries 
where  the  governments  have  caused  trenches  to  be  con- 
structed, in  which  the  cultivators  of  lands  might  deposit 
their  harvest  till  a  favorable  season  for  selling  them. 

In  order  to  secure  a  perfect  preservation  of  the  grain  in 
trenches,  it  is  necessary  to  make  use  of  certain  precau- 
tions, without  which  the  entire  loss  of  it  must  be  hazard- 
ed :  the  means  of  security  are  as  follows. 

1st.  The  grain  should  never  be  put  into  trenches  till 
it  is  perfectly  dry  ;  it  must  therefore  be  first  exposed  to  the 
sun  for  several  days,  and  during  that  time  be  often  turned, 
that  every  part  of  it  may  become  equally  dry. 

2d.  In  constructing  the  trenches,  choice  must  be  made 
of  a  dry  soil,  or  a  rock  free  from  chinks,  that  there  may 
be  no  danger  either  from  dampness  or  the  filtration  of 
water.  The  walls  of  the  trenches  may  be  made  with  such 
cement  as  the  Romans  used  in  the  construction  of  their 
aqueducts  ;  this  is  composed  merely  of  lime  and  pebbles  ; 
the  walls  of  these  aqueducts  were  raised  in  frames,  and 
the  surface  of  them  carefully  polished  ;  I  have  visited  the 
remains  of  some  of  them  in  various  parts  of  France,  and 
have  found  them  everywhere  present  the  same  appear- 
ance :  I  am  convinced  that  this  cement  is  impenetrable  by 
water,  and  of  a  solidity  more  than  sufficient  for  construct- 
ing the  sides  of  trenches.* 

3d.  The  third  precaution  consists  in  excluding  the  air 
completely ;  if  this  fluid  should  gain  admittance,  it  must 
necessarily  convey  in  at  the  same  time  moisture  and  oxy- 
gen, the  two  principles  of  germination  ;  the  presence  of 
air  will  likewise  favor  the  existence  and  multiplication  of 
insects  ;  whilst  if  the  trench  be  full  of  grain,  and  well 
closed,  all  the   air  which   it  contains  will  be  changed  into 

*  The  mode  of  building  may  be  used  which  the  Count  of  Lasteyrie 
has  proposed  in  his  work,  entitled  Des  Fosses  pour  la  Conservation  d^s 
Grains. 

17 


194  CHYMISTRY    APPLIED    TO    ACRICULTURE. 

carbonic  acid,  (as  I  have  explained  in  speaking  of  the 
action  of  air  upon  fruits,)  and  the  insects  will  remain  tor- 
pid. This  last  assertion  is,  as  we  shall  shortly  see,  sup- 
ported by  the  results  of  the  experiments  which  have  been 
made  by  the  Board  of  Provisions  of  War,  for  the  purpose  of 
ascertaining  the  best  mode  of  preserving  grain. 

But  the  construction  of  these  trenches,  as  it  involves 
some  expense,  and  requires  much  care,  will  be  for  a  long 
time  rejected  by  mere  farmers.  However  advantageous 
this  arrangement  may  be,  it  belongs  entirely  to  public  au- 
thorities, great  cities,  and  governments,  to  set  an  example 
of  the  use  of  it,  by  withdrawing  from  circulation,  during 
years  of  abundant  harvests,  large  quantities  of  corn  to  be 
deposited  in  trenches  and  preserved  against  years  of  scarci- 
ty. Much  has  been  written,  within  a  few  years,  upon  the 
best  methods  of  preserving  grain  ;  but  all  those  that  have 
been  proposed  were  founded  upon  the  same  principles. 

The  Board  of  Provisions  of  War,  under  the  direction  of 
Count  Dejean,  has  performed  a  series  of  well-directed  ex- 
periments, from  which  excellent  results  have  been  obtain- 
ed :  the  apparatus  used  in  them  consisted  of  lead  receivers 
hermetically  sealed  and  having  all  their  joinings  soldered. 
Meal  and  grain  full  of  weevils  were  enclosed  in  three  re- 
ceivers ;  when  these  were  opened,  at  the  end  of  a  year,  it 
was  found  that  no  injury  had  been  done  by  the  weevils ; 
they  were  all  either  dead  or  in  a  state  of  torpor.  In  one 
of  the  receivers  there  was  found  a  collection  of  grains  ad- 
hering to  each  other  in  a  mass  about  as  large  as  a  mid- 
dling-sized apple  :  this  arose  from  the  entrance  of  air  and 
moisture  through  a  hole  the  size  of  a  pin,  accidentally  left 
unsoldered  in  one  of  the  joints. 

The  elder  M.  Ternaux  caused  trenches  to  be  formed 
and  filled  with  corn  in  the  beautiful  field  of  Saint  Arven  ; 
in  order  to  be  sure  of  the  preservation  of  the  grain,  he 
caused  the  trenches  to  be  opened  from  year  to  year,  and  the 
results  were  always  satisfactory. 

Corn,  well  dried  and  guarded  from  air  and  moisture, 
may  be  preserved  in  the  ear  for  a  long  time,  and  it  is  a 
well-known  fact  that  in  some  agricultural  countries  the 
sheaves  are  formed  into  stacks  which  are  taken  down 
either  for  consumption  or  the  market,  at  those  times  when 
the  laborers  upon  the  farm  can  be  employed  only  in  thresh- 
ing in  a  barn. 

Instead  of  constructing  trenches  of  stone  without  the 


PRESERVATION  OF  FRUITS  BY  SECLUSION.      195 

farm  buildings,  there  might  be  built,  within  them,  bins  of 
stone,  of  a  size  proportioned  to  the  produce  of  the  farm, 
and  with  the  openings  covered  in  such  a  manner  as  to  ex- 
clude the  air.  The  same  purpose  may  be  answered  by 
chests  and  tubs  of  wood  having  their  outsides  covered 
with  a  thick  coat  of  oil  paint.  The  great  earthen  jars 
in  which  oil  is  kept  at  the  south,  are  likewise  very  good 
for  keeping  grain  in. 

Either  of  these  methods  is  preferable  to  that  of  storing 
grain  in  such  granaries  as  are  commonly  used,  since  the 
utmost  care  will  not  entirely  protect  it  from  moisture,  in- 
sects, mice,  &c.,  nor  will  it  often  remain  in  them  un- 
changed beyond  three  or  four  years. 

Corn  which  is  housed  without  being  thoroughly  dried, 
or  which  is  stored  in  a  damp  place,  acquires  a  musty  smell 
and  taste,  which  render  it  unfit  for  the  customary  uses  : 
but  as  this  alteration  affects  only  the  outer  covering,  and  not 
the  substance  of  the  kernel,  it  may  be  easily  removed  by 
throwing  upon  the  grain  double  its  weight  of  boiling  water, 
carefully  stirring  the  mass  till  the  water  becomes  cold. 
The  spoiled  kernels,  which  swim  upon  the  top,  must  then 
be  removed,  the  water  poured  off,  and  the  grain  spread  to 
dry.  M.  Peschier  preferred  employing  for  this  purpose 
•boiling  water  rendered  slightly  alkaline,  and  afterwards 
washing  the  grain  in  pure  water.* 

When  corn  has  been  heated  or  injured  in  a  perceptible 
manner,  the  vegeto-animal  portion  is  almost  always  chang- 
ed;  in  this  case  the  farina  is  not  susceptible  of  a  good 
fermentation,  and  the  bread  made  from  it  is  unwholesome  : 
such  grain  is  fit  only  for  the  manufactory  of  starch. 

The  modes  of  preserving  vegetable  juices  and  other  arti- 
cles of  food  deserve  also  much  attention. 

The  substances  of  which  I  shall  now  speak  present  the 
alimentary  principle  so  mixed  with,  or  dissolved  in  the 
aqueous  fluid,  as  to  render  them  exceedingly  susceptible 
of  alteration  and  decomposition.  It  is  not  sufficient  to  se- 
clude these  from  the  air,  since  they  contain  for  the  most 
part  within  themselves  those  principles  of  fermentation, 
which,  acting  upon  each  other,  produce  decomposition. 

Seclusion  from  the  air  alone  will  not  preserve  these  sub- 
stances ;  the  nature  of  some  of  the  fermentative  principles 
must  be  changed ;  and  for  effecting  this  I  would  recom- 

*  AnndLes  de  Ckimie  et  de  Physique^  tome  VI.  page  87. 


196  CIIYMISTRY    APPLIED    TO   AGRICULTURE. 

mend  the  preserving  process  made  use  of  by  M.  Apperf, 
and  confirmed  by  numberless  experiments.  I  shall  here  only 
make  mention  of  the  mode  of  preservation  ;  as  the  work  of 
M  Appert  is  before  the  public,  it  may  be  consulted  in  re- 
gard to  the  necessary  details  respecting  each  operation.* 

The  process  consists, 

1st.  In  putting  up,  in  glass  jars  or  bottles,  those  solid 
or  liquid  substances  which  are  to  be  preserved. 

2dly.     In  corking  the  bottles  carefully. 

3dly.  In  placing  these  vessels  upright  in  a  boiler  filled 
with  cold  water,  as  high  as  the  ring  of  the  bottles. 

4thly.  In  causing  the  water  to  boil,  and  continuing  the 
ebullition  for  a  longer  or  shorter  time,  according  to  the 
nature  of  the  substance  contained  in  the  vessels. 

In  this  process  we  see  that  nothing  more  is  required  than  a 
boiler  and  some  bottles  or  jars  ;  it  is  one  that  may  be  prac- 
tised in  the  smallest  domestic  establishment.  In  order 
however  to  avoid  accidents  and  insure  success,  certain 
precautions  in  each  part  of  the  process  are  necessary  :  the 
principal  of  these,  especially  those  that  are  indispensable, 
I  shall  here  point  out. 

The  choice  of  bottles  is  a  matter  of  some  consequence : 
the  form  of  the  champagne  bottles  is  the  best,  and  as  the 
glass  of  these  is  of  a  more  uniform  thickness  than  that  of 
others,  it  is  generally  better  annealed  ;  these  bottles  then 
should  be  preferred,  particularly  if  they  have  proved  their 
soundness  by  having  resisted  the  action  of  the  compressed 
air  contained  in  foaming  wine. 

Too  much  care  cannot  be  taken  in  the  choice  of  corks ; 
only  the  superfine  should  be  used,  and  these  should  be  free 
from  defects.  The  length  of  the  corks  should  be  at  least 
eighteen  or  twenty  lines,  and  the  diameter  a  little  greater 
than  that  of  the  mouth  of  the  bottles,  into  which  they  must 
be  forced  by  blows  of  a  mallet. 

The  bottles  must  be  filled  within  three  inches  of  the 
ring ;  the  corks  selected  for  them  must  be  softened  a  little 
in  water ;  in  stopping  a  bottle,  put  the  small  end  of  the 
cork  into  the  mouth  of  the  bottle,  and  force  it  in  as  far  as 
possible  with  the  hand  ;  then  wrap  the  bottle  in  a  towel, 
and,  holding  the  neck  of  it  firmly  in  the  left  hand,  drive 


*  Le  Livre  de  tons  les  Manages,  ou  UArt  de  conserver  pendant 
plusieurs  annees  toutes  les  Substances  Jlnimales  et  V6g6tales.  18H,. 
2«  6(iition  \  par  M.  Appert. 


PRESERVATION    OF    FRUITS    BY    SECLUSION.  197 

the  cork  in  by  repeated  blows  with  a  mallet ;  a  few  lines 
of  the  length  of  the  cork  must  be  left  beyond  the  mouth 
of  the  bottle  to  receive  the  wire  or  twine  with  which  it 
is  to  be  secured.  Each  bottle  is  then  to  be  put  into  a 
bag  of  strong  linen,  which  will  cover  it  to  the  cork,  and 
placed  in  a  boiler  filled  with  water  to  the  rings  of  the 
bottles.  The  boiler  is  to  be  covered,  and  over  the  lid 
must  be  placed  a  damp  linen  cloth,  to  secure  the  retention 
of  the  heat.  The  apparatus  being  thus  prepared,  the 
water  may  be  heated  to  boiUng,  and  continued  in  that  state 
as  long  as  the  nature  of  the  substance  to  be  preserved 
requires. 

When  the  fire  has  been  removed  from  the  fire-place  a 
quarter  of  an  hour,  the  water  must  be  drawn  off  by  means 
of  a  siphon,  or  of  a  stop-cock  placed  near  the  bottom  of 
the  boiler  ;  the  cover  must  not  be  removed  to  take  out  the 
bottles  till  fifteen  minutes  afl;er  the  water  has  been  drawn 
off.* 

When  meat  or  other  solid  food  is  to  be  preserved,  wide- 
mouthed  bottles  or  jars  may  be  used  in  the  same  manner 
as    the   narrow-necked   bottles    mentioned    above.      Good 


[*  The  translator  of  this  work  has  preserved  the  most  delicate  fruit 
by  a  process  somewhat  similar  to  the  one  here  described,  but  with  one 
pretty  important  difference.  As  the  preservation  of  the  fruit  seems 
to  depend  wholly  upon  the  exclusion  of  the  air,  which  would  not  be 
effected  by  corkmg  the  bottles  before  exposing  them  to  heat,  and  as 
the  bottles  would  be  in  great  danger  of  being  burst  by  the  expansion 
of  the  air  contained  not  only  in  the  fruits  themselves,  but  in  the 
interstices  which  must  unavoidably  occur  between  them,  the  above 
method  appears  to  be  an  imperfect  one  ;  she  therefore  .takes  the  liberty 
of  inserting  in  this  note  the  process  which  she  has  used  successfully, 
and  particularly  as  she  has  found  fruit  thus  preserved  exceedingly 
grateful  in  sickness  at  those  seasons  of  the  year  when  no  fresh  fruit 
could  be  procured,  and  when  that  which  was  done  with  sugar  was 
neither  suitable  nor  agreeable. 

Pick  carefully  over  the  fruit  to  be  bottled  so  as  to  take  only  such 
as  is  perfectly  sound,  and  put  it  in  bottles  having  wide  mouths  with 
closely  fitting  corks,  shake  the  fruit  well  down  so  as  to  leave  as  little 
space  unoccupied  as  possible  in  the  bottles ;  when  they  are  quite  full, 
set  them  uncorked  into  a  boiler  of  cold  water  over  tlie  fire,  raise  the 
temperature  of  the  water  as  quickly  as  possible  to  the  boiling  point, 
and  as  soon  as  ebullition  takes  place,  put  the  corks  into  the  bottles, 
and  remove  them  from  the  boiler ;  some  ready  melted  cement, 
such  as  is  commonly  used  for  closing  bottles,  must  be  immediately 
applied  over  the  corks,  and  the  fruit  having  been  freed  by  the  heat 
from  the  air  contained  within  the  bottles  will  thus  be  protected  from 
the  action  of  the  external  air,  and  may  be  preserved  fresh  for  many 
months. — Tr.l 

17  ♦ 


198  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

gravy  of  meat,  and  beef  three  quarters  cooked,  when  pre- 
pared according  to  the  foregoing  directions,  have  been 
found  as  good  after  being  eighteen  months  at  sea,  as  when 
first  put  up.  Attention  must  be  paid  in  putting  up  solid 
articles  in  bottles,  to  pack  them  closely,  in  order  that  as 
little  air  as  possible  may  interpose  between  the  pieces. 
Consommes,  strong  decoctions,*  and  jellies  of  meat  con- 
taining all  those  portions  of  it  most  nourishing  to  man, 
may  be  thus  preserved  uninjured  for  a  long  time. 

Before  milk  is  put  into  bottles  for  keeping,  it  should  be 
evaporated  in  a  water  or  vapor  bath,  and  the  scum  which 
forms  upon  the  top  carefully  removed;  half  an  hour  be- 
fore evaporation  is  completed,  there  should  be  mixed  with 
every  pint  of  the  reduced  milk,  the  yolk  of  an  egg  well 
beaten.  After  being  thoroughly  cooled  the  milk  must  be 
put  into  bottles,  and  corked  tightly,  to  undergo  the  second 
scalding.  Milk  preserved  in  this  way  has  been  found  at 
the  end  of  two  years  to  be  unchanged,  and  to  afford  butter 
and  butter-milk  the  same  as  if  new.  It  is  not  however 
pretended,  that  it  preserves  all  the  qualities  of  new  milk; 
it  almost  always  has  a  peculiar  odor  and  taste,  but  such 
as  it  is,  it  forms  an  agreeable  and  a  valuable  article,  for  sea 
stores  for  long  voyages. 

Cream  evaporated  one  fifth  part  and  put  into  bottles 
after  having  had  the  skin  coagulated  upon  the  surface  re- 
moved from  it,  and  then  subjected  to  a  second  scalding 
for  an  hour,  has  not  been  sensibly  altered  at  the  end  of  two 
years.       * 

Those  vegetables  of  which  so  much  use  is  made  in  all 
families,  may  be  preserved  in  the  same  manner ;  they  are, 
however,  boiled  a  shorter  time,  and  some  of  them  must 
previously  undergo  a  degree  of  preparation.  For  instance, 
in  preserving  asparagus  it  is  necessary,  after  having  wash- 
ed it,  to  plunge  it  first  into  boiling  and  then  into  cold  water, 
to  deprive  it  of  its  acrid  taste  ;  it  afterwards  receives  but  a 
slight  scalding. 

To  preserve  the  color  of  the  small  bush-beans,  bottles 
filled  with  them  are  plunged  into  very  cold  water,  where 
they  remain  for  an  hour  ;  they  are  then  drawn  out,  corked, 
wired,  and  scalded  for  an  hour.  Artichokes,  after  having 
had  boiling  water  poured  over  them,  are  washed  in  cold 
water,  drained,  and  scalded   in  the   bottles    for    an    hour. 

*  Answering  to  "  portable  soups." 


PRESERVATION    OF    FRUITS    BY    SECLUSION.  199 

Cauliflowers  are  prepared  in  the  same  way  as  artichokes, 
excepting  that  they  are  boiled  but  half  an  hour.  Legumes 
in  general,  prepared  and  seasoned,  and  put  into  bottles 
when  three  quarters  cooked,  will  keep  very  well  with  being 
scalded  twenty  minutes. 

Antiscorbutic  plants,  and  the  juices  which  are  extracted 
from  all  fruits  and  vegetables,  require  only  to  be  scalded. 
When  juices  are  to  be  kept,  they  should  be  carefully 
strained  and  clarified  ;  plants  require  to  be  well  washed, 
picked  and  dried,  and  to  be  crowded  into  the  bottles. 
When  any  of  these  preparations  are  made  use  of,  they 
should  be  dressed  in  such  a  manner  as  to  give  them  the 
appearance  of  those  prepared  daily  in  our  kitchens. 

Those  articles  that  have  been  cooked  before  being  put 
into  bottles,  only  require  to  be  heated. 

The  strong  decoctions  will  need  the  addition  of  nothing 
but  water  to  become  good  broth. 

The  jellies  of  beef,  veal,  mutton,  chickens,  &c.,  when 
diluted  with  water,  and  seasoned  with  salt,  make  excellent 
soups. 

The  legumes  must  be  washed  upon  being  taken  from  the 
bottles,  and  then  prepared  as  if  fresh. 

The  juices  may  be  appropriated  as  usual,  either  for  food, 
drink,  or  medicine. 

I  shall  close  this  article  by  observing,  that  some  bodies 
are  preserved  from  destruction,  and  guarded  from  the  at- 
tacks of  insects,  and  the  action  of  air  and  water,  by 
means  of  a  coat  of  varnish  laid  upon  the  surface  of  them  ; 
this  practice  has  become  very  common,  and  when  the 
varnish  is  applied  to  bodies  well  dried,  and  does  not  scale 
off,  it  preserves  them  a  long  time.  Oil  paints  and  tar  pro- 
duce the  same  effect. 

The  custom  of  preserving  eggs  by  immersing  them  in 
lime  water  has  lately  been  introduced  into  Paris ;  the 
shell  of  the  egg  thus  immersed  becomes  covered  with  a  thin 
coat  of  lime,  which  preserves  its  contents  unchanged. 


200  CHYMISTRY    APPLIED    TO    AGRICULTURE. 


ARTICLE  III. 

On  the  Preservation  of  certain  Articles  of  Food  hy  means 
of  Salt  and  Spirituous  Liquors. 

Most  of  the  articles  employed  as  food,  or  other  domestic 
purposes,  may  be  prepared  by  the  following  methods. 

1.  By  immersing  them  in  liquids  which  will  not  dissolve 
them,  and  which  will  not  themselves  be  changed  by  time. 

2.  By  combining  them  with  other  bodies  with  which  they 
form  indestructible  compounds. 

3.  By  saturating  them  with  salts. 

In  the  first  method  the  liquor  usually  employed  is  either 
alcohol  or  brandy ;  many  other  fluids,  as  the  acids, 
oil,  &c.,  might  be  made  use  of,  but  these  alter  the  taste, 
and  change  the  qualities  of  the  greater  part  of  the  sub- 
stances, which  are  designed  for  food.  Nearly  all  kinds 
of  fruit  may  be  preserved  in  alcohol,  but  it  is  used  only 
for  those  of  small  size,  as  it  cannot  penetrate  throughout 
the  substance  of  the  larger  kinds,  and  consequently  they 
are  liable  to  decay  ;  I  shall  therefore  mention  only  the  modes 
of  preserving  cherries  and  plums  in  brandy. 

The  juice  of  six  pounds  of  early  and  very  ripe  cherries 
put  into  a  sauce-pan,  with  three  pounds  of  powdered 
sugar,  is  set  over  a  fire  and  made  to  boil  for  half  an  hour  ; 
the  sauce-pan  is  then  removed  from  the  fire,  and  a  pound 
of  ripe  raspberries  is  thrown  into  the  liquor  and  pressed 
down  with  a  skimmer  ;  to  the  whole  is  added  six  pints  of 
brandy  flavored  with  some  aromatic,  such  as  cloves,  cinna- 
mon, vanilla,  &lc.  This  preparation  is  preserved  in  close 
jars  set  in  the  sun. 

As  soon  as  the  large  cherries  are  ripe,  the  preparation 
of  brandy,  mentioned  in  the  last  paragraph,  is  to  be  strain- 
ed and  then  put  into  glass  jars  filled  with  the  fruit  to  be 
preserved  ;  these  jars  are  placed  on  windows  exposed  to  the 
sun,  till  the  fruit  becomes  penetrated  by  the  liquor. 

Plums  are  prepared  in  a  somewhat  different  manner.  For 
preserving,  take  the  finest  green  gages,  prick  them,  and 
put  them  into  a  sauce-pan  with  cold  water ;  set  the  sauce- 
pan on  the  fire,  and  as  fast  as  the  plums  rise,  remove  them 
with  a  skimmer,  and  throw  them  into  cold  water  ;  dissolve 
two  pounds  of  sugar  in  two  pounds  of  hot  water,  and 
when  the  sirup  is  cold,  throw  the  plums  into  it,  and  allow 


PRESERVATION    OF   FOOD   BY    MEANS    OF    SALT,  &C.     201 

them  to  remain  in  it  at  a  gentle  heat  for  some  time  ; 
when  the  fruit  is  penetrated  by  the  sugar,  remove  it, 
evaporate  the  sirup,  put  the  fruit  again  into  it,  and  treat 
it  as  before ;  after  which,  remove  it  again,  and  evaporate 
the  sirup  till  it  becomes  tenacious,  then  return  the  plums 
to  it  for  the  last  time.  When  the  whole  is  cold,  put  it  into 
bottles  with  a  quantity  of  brandy  equal  to  that  of  the 
plums  and  sirup.  The  unbroken  plums  alone  must  be  put 
up  in  this  way. 

The  description  of  this  process  is  a  sufficient  guide  for 
those,  who  wish  to  preserve  other  fruits  in  the  same  way. 

When  sirups  are  used  instead  of  sugar,  a  greater  quantity 
of  brandy  than  that  mentioned  is  necessary  to  preserve  the 
fruits  unchanged. 

Alcohol  dissolves  and  retains  the  aroma  of  plants  ;  it  is 
only  necessary  to  make  an  infusion  of  the  plant  or  flower 
in  alcohol,  and  afterwards  to  pass  the  liquor  through  a 
filter. 

I  do  not  hesitate  to  direct  in  this  work  certain  methods 
of  obtaining  spirituous  liquors,  which,  when  used  sparing- 
ly, appear  to  me  to  be  serviceable  in  preserving  the  health 
of  country  people.  I  feel  that  I  ought  not  to  aim  at  giving 
these  drinks  the  qualities  required  by  the  luxurious,  and 
those  of  delicate  and  refined  taste,  but  direct  such  methods 
of  obtaining  them  as  are  consistent  with  the  most  rigid 
economy,  and  with  the  employment  of  such  materials  as 
every  mistress  of  a  family  has  within  her  control. 

To  make  three  pints  of  ratafia  of  nuts,  crack  two  hundred 
apricot  stones  from  which  the  pulp  has  been  separated ; 
spread  the  kernels  in  the  sun,  and  after  they  are  sufficiently 
dry,  pound  them  in  a  mortar,  and  put  them  into  a  bottle 
with  a  quart  of  brandy  ;  cork  the  bottle  carefully  and  set  it 
in  the  sun.  After  twenty  days,  strain  the  liquor  and  add  to  it 
a  pound  and  a  half  of  sugar  dissolved  in  half  a  pint  of 
water,  or  two  pounds  and  a  half  of  good  sirup  ;  if  a  portion 
of  almonds  be  mixed  with  the  apricot  kernels,  the  flavor  of 
the  liquor  will  be  improved. 

Some  ratafia  is  made  of  almonds  alone  ;  in  this  case  the 
kernels  are  thrown  into  boiling  water  to  deprive  them  of 
their  outer  skin ;  they  are  then  bruised  in  a  marble  or 
wooden  mortar,  with  a  little  water  and  sugar,  and  this 
paste  is  put  into  a  bottle  with  brandy  ;  after  having  been 
exposed  several  days  to  the  sun,  the  liquor  is  strained,  and 
a  suitable  portion  of  sirup  added  to  it.     Very  good  ratafia 


202  CHYMISTRY   APPLIED   TO   AGRICULTURE. 

is  made  from  almonds  and  the  kernels  of  peaches  pounded 
together. 

The  base  of  all  liquors  of  this  kind  is  brandy  and  sugar  ; 
the  difference  in  their  flavor  arises  from  the  aroma  and  other 
portions  of  vegetables  incorporated  with  them. 

The  best  mode  of  proceeding  is,  to  prepare  first  a  liquor, 
by  dissolving  eight  pounds  of  sugar  in  three  times  its  weight 
of  water ;  this  must  be  boiled  and  skimmed,  and  when  all 
the  sugar  is  dissolved,  the  liquor  must  be  strained  and  put 
into  a  jug  with  ten  pints  of  brandy,  the  jug  carefully  corked 
and  set  in  a  cool  place.  Into  this  liquor  various  substances 
calculated  to  gratify  the  taste  and  smell  may  be  put ;  when 
a  portion  of  it  is  to  be  used,  it  is  to  be  poured  into  a  sauce- 
pan, and  after  being  slightly  warmed,  the  flavoring  designed 
for  it  is  to  be  added. 

For  orange-flower  water,  make  an  infusion  of  the  petals 
of  the  flower,  filtrate  it  through  paper,  and  add  of  sugar  one 
eighth  of  the  weight  of  the  flowers. 

When  the  liquor  is  to  be  flavored  with  citron,  orange, 
bergamot,  or  lemon,  the  surface  of  the  fruits  may  be  grated 
with  bits  of  sugar,  which  imbibe  the  volatile  oil  contained  in 
small  vessels  in  the  rind,  and  the  sugar  thus  saturated  with 
aroma  is  dissolved  in  the  liquor.  Vanilla,  cinnamon,  and 
clove  may  be  used  for  the  same  purpose. 

Liquors  are  sometimes  made  with  the  juices  of  fruits  well 
refined. 

I  will  here  give  as  an  example  the  ratafia  o^ four  fruits. 

After  having  expressed  the  juice  from  ten  pounds  of 
cherries,  and  as  many  of  currants,  five  pounds  of  raspber- 
ries, and  five  pounds  of  black  currants  and  of  bitter  cher- 
ries, add  to  each  pint  of  the  juice  one  pint  of  good  brandy, 
and  allow  it  to  remain  undisturbed  twenty-four  hours  ;  at 
the  end  of  that  time  strain  the  liquor  and  add  to  each  pint 
of  it  eight  ounces  of  sugar;  six  weeks  after,  the  liquor  must 
be  again  strained,  and  an  additional  flavor  may  be  given  it 
if  desired,  by  adding  to  it  a  little  cinnamon,  or  clove-water, 
pounded  coriander  seeds,  or  bitter  almonds. 

All  animal  substances  may  be  preserved  from  putrefac- 
tion in  alcohol ;  anatomical  preparations  and  some  entire 
animals  are  kept  in  this  liquid ;  but  it  is  necessary  that 
the  alcohol  employed  for  this  purpose  be  of  the  best  kind 
to  be  found  in  commerce ;  if  it  should  contain  any  con- 
siderable proportion  of  watery  particles,  those  portions 
of  animal   matter  which   are   soluble  would   be   dissolved 


PRESERVATION    OP    FOOD    BY    MEANS    OF    SALT,    &C.    203 

and  corrupted.  Care  must  likewise  be  taken  that  the  jars, 
in  which  these  substances  are  put,  be  hermetically  sealed, 
as  otherwise  the  alcohol  will  be  lost  by  evaporation. 

There  is  another  way  in  which  animals  of  a  small  size 
may  be  perfectly  preserved  by  means  of  alcohol ;  of  this  I 
am  convinced  by  some  experiments  which  I  have  made 
with  the  most  satisfactory  results,  upon  birds,  in  the  fol- 
lowing manner.  Having  suspended  the  bird  by  the  beak, 
the  vent  being  secured  by  a  thread,  I  fitted  a  little  tunnel 
to  the  throat,  and  thus  filled  the  crop  and  intestines  with 
very  pure  alcohol ;  as  soon  as  this  was  evaporated,  I  poured 
in  a  fresh  portion,  and  repeated  this  till  the  flesh  was  as 
dry  as  tinder.  In  this  way  the  form  of  an  animal  may  be 
perfectly  preserved. 

The  second  means  of  preservation  of  which  I  spoke  at 
the  commencement  of  this  article,  consists  in  bringing 
these  substances  into  union  with  such  bodies  as  will  form 
with  them  indestructible  compounds.  The  conversion  of 
skin  into  leather  is  the  most  striking  instance  I  can  bring 
of  this  process :  this  is  done  by  causing  the  tannin  of 
certain  vegetables  to  combine  with  the  gelatine,  which 
forms  nearly  the  whole  substance  of  skin  :  from  this  union 
there  results  a  hard,  indestructible  compound,  preserving 
the  original  form  of  the  skin,  but  with  increased  weight. 

The  third  mode  of  preserving  bodies,  is  to  incorporate 
them  with  salts  unalterable  by  the  air,  which,  penetrating 
the  whole  tissue  of  the  substance,  prevent  decomposition : 
this  is  the  most  valuable  and  generally  practised  method  of 
preserving  meat  and  fish,  and  the  articles  thus  prepared 
form  an  extensive  branch  of  commerce  between  different 
nations ;  a  supply  of  food  which  would  otherwise  be  want- 
ing, is  thus  provided. 

The  best  salted  provisions  were  formerly  fiirnished  by 
Ireland,  and  that  country  still  carries  on  a  very  extensive 
traffic  in  them,  though  the  same  methods  practised  there, 
have  been  adopted  by  the  Danes  and  other  nations.  I  shall 
here  describe  succinctly  the  modes  made  use  of* 

For  salting,  the  fattest  oxen  of  from  five  to  seven  years 
old  are  chosen ;  before  that  age,  the  flesh  has  not  sufficient 
firmness,  and  afl:er  that  period,  it  is  too  hard. 

When   the   animals  have   been  driven   fi-om  a  distance, 

*  The  fullest  statements  may  be  found  in  the  work  of  M.  Martfelt^ 
translated  from  the  Danish,  by  M.  Bruun-Neergaard. 


204  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

they  are  not  killed  till  two  days  after  their  arrival,  and  in 
the  interval  are  allowed  only  water :  before  being  killed, 
they  should  be  bled  freely,  that  all  the  blood  may  be  drawn 
out  of  the  body ;  and  even  after  using  this  precaution,  it  is 
necessary,  when  the  meat  is  cut  up,  to  remove  the  blood 
very  carefully  from  the  pieces. 

The  carcasses  should  not  be  cut  up  till  the  animals  have 
been  dead  twenty-four  hours,  and  when  this  is  done,  all  the 
marrow  must  be  carefully  removed  from  the  bones. 

The  salt  employed  should  be  perfectly  clean,  and  of  a 
fine  and  heavy  kind :  the  fine  salt  of  Portugal  is  esteemed 
the  best. 

The  proportion  of  salt  to  meat  should  be  in  volume,  as  24 
to  100.  If  only  the  Lisbon  salt  be  used,  the  proportion  is 
as  2  to  7^^ :  in  general  the  proportion  in  weight  is  as  1  of 
salt  to  6  of  meat. 

That  the  salt  may  penetrate  the  meat  quickly,  the  salters 
have  a  leather  guard  or  a  glove  shod  with  iron  upon  the 
right  hand  ;  this  glove  is  composed  of  two  or  three  pieces 
of  sole-leather,  united  by  nails  with  rough,  broken  heads ; 
a  strap  of  leather  serves  to  keep  it  on,  and  it  thus  forms  a 
sort  of  flesh-brush,  with  which  the  blood  can  be  pressed 
out  of  the  meat,  and  the  salt  rubbed  into  it.  Each  piece 
of  meat  passes  through  the  hands  of  a  series  of  salters, 
who  execute  upon  it  the  same  operation,  and  when  it  arrives 
at  the  last,  who  is  the  most  experienced  and  skilful,  he 
examines  to  see  if  there  be  any  defect  in  it,  any  vein  which 
requires  to  be  opened ;  he  corrects  the  defects,  opens  the 
veins,  rubs  in  more  salt,  and  throws  it  into  the  cask  of 
salted  pieces  :  in  this  it  remains  in  the  air  eight  or  ten 
days,  the  salt  penetrates  into  it,  and  is  turned  into  brine  : 
at  the  end  of  this  time  it  is  taken  out  and  barrelled.  After 
the  meat  is  removed  from  the  cask,  the  brine  is  thrown  into 
a  trough,  and  a  layer  of  salt  put  at  the  bottom  of  the  cask ; 
upon  this  is  placed  a  layer  of  meat,  and  thus  alternately 
till  the  cask  is  full.  Attention  must  be  paid  to  putting  the 
pieces  of  inferior  quality  at  the  bottom  of  the  cask,  those 
of  the  better  kind  in  the  middle,  and  the  best  at  top.  When 
the  meat  is  all  packed  in,  it  must  be  pressed  down  with  a 
weight  of  fifty  pounds,  and  the  cask  closed. 

There  must  afterwards  be  a  hole  bored  in  one  end  of  the 
cask,  to  blow  into,  in  order  to  be  sure  that  it  does  not  leak : 
if  no  air  escapes,  the  hole  is  closed  again :  if  the  contrary 
be  the  case,  the  aperture  through  which  it  passes  is  sought 


PRESERVATION    OF   FOOD    BY   MEANS    OF    SALT,  &C.      205 

for.  When  it  is  ascertained  that  the  cask  is  in  good  order,  the 
bung  is  taken  out,  and  the  brine  turned  in  till  the  meat  is 
saturated  and  covered  :  the  less  brine  is  required,  the  better 
will  the  meat  keep. 

After  having  allowed  the  barrels  to  remain  five  days,  it  is 
necessary  to  examine  whether  they  are  well  filled  with  brine, 
and  if  not,  it  must  be  added  till  they  can  contain  no  more  : 
they  must  then  be  again  blown  into  to  be  certain  that  they 
can  lose  none,  and  then  the  operation  is  ended. 

Tongues  are  salted  in  separate  casks. 

The  manner  in  which  pork  is  salted  does  not  differ  from 
that  which  I  have  just  described  as  used  for  beef,  excepting 
that  the  fat  is  rubbed  less. 

In  Hamburg  the  art  of  smoking  beef  has  been  carried 
to  a  degree  of  perfection  not  attained  elsewhere ;  and  the 
smoked  beef  of  Hamburg  enjoys  everywhere  the  highest 
reputation. 

For  this  purpose  the  fattest  cattle  of  Jutland  and  Holstein 
are  preferred,  and  these  must  be  of  a  middling  age.  The 
meat  is  salted  with  English  salt ;  the  stronger  salts,  as  those 
of  Portugal,  deprive  the  meat  of  its  natural  taste,  and  as  the 
process  of  smoking  contributes  to  preserve  it  from  injury, 
that  of  salting  does  not  require  so  much  care. 

To  preserve  the  red  color  of  the  meat  as  much  as  possible, 
a  certain  quantity  of  salt-petre  is  added  to  the  English  salt, 
and  the  meat  is  allowed  to  remain  in  it  eight  days  before 
being  smoked. 

Fires  of  oak  chips  are  built  in  cellars,  from  whence  the 
smoke  is  conveyed  by  two  chimneys  into  the  fourth  story, 
and  throvi^n  into  a  chamber  by  two  openings  placed  the  one 
opposite  the  other.  The  size  of  the  chamber  is  proportion- 
ed to  the  quantity  of  meat  to  be  smoked,  but  the  ceiling  is 
not  raised  more  than  five  feet  and  a  half  fi-om  the  floor. 
Above  this  chamber  there  is  another  made  of  boards,  into 
which  the  smoke  passes  through  a  hole  in  the  ceiling  of  the 
first,  whence  it  escapes  by  openings  formed  in  the  sides. 
The  pieces  of  meat  are  hung  up  in  the  first  chamber,  at  the 
distance  of  a  foot  and  a  half  from  each  other,  and  a  fire  is 
kept  up  night  and  day  for  a  month  or  six  weeks,  according 
to  the  size  of  the  pieces. 

The  sausages  are  suspended  in  the  second  chamber,  and 
the  largest  of  them  allowed  to  remain  there  six  or  eight 
months. 

In  this  process  two  means  of  preservation  are  combined  : 
18 


206  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

the  first  is  the  action  of  salt,  and  the  second  that  of  the 
pyroligneous  acid,  which'  is  furnished  by  combustion,  and 
which  constitutes  by  far  the  greater  part  of  smoke  :  this 
acid,  as  I  have  found  by  repeated  experiments,  penetrates 
the  meat  and  preserves  it  from  putrefaction,  but  when  em- 
ployed alone,  the  meat  becomes  hard,  and  acquires  a  disa- 
greeable blackish  hue. 

Animal  substances,  by  being  immersed  in  a  weak  acid, 
or  in  water  acidulated  with  sulphuric  acid,  may  be  preserved 
a  long  time  without  undergoing  putrefaction,  but  this  process 
is  not  applicable  to  such  as  are  designed  for  food. 

Other  salts  may  be  employed  as  substitutes  for  marine 
salt ;  but  besides  being  more  costly,  they  are  either  injurious 
to  the  health,  or  give  to  the  meat  a  disagreeable  taste,  of 
which  it  cannot  be  entirely  deprived. 

Butter  is  a  valuable  article  of  food,  and  forms  a  great  re- 
source for  the  inhabitants  of  the  country ;  but  in  those  re- 
gions where  the  extent  and  fertility  of  the  pasture  lands  per- 
mits great  numbers  of  horned  cattle  to  be  raised,  it  is  im- 
possible for  them  to  consume  all  the  butter  they  make,  whilst 
it  is  fresh ;  and  besides,  as  the  quantity  of  butter  made  is 
not  the  same  at  all  seasons  of  the  year,  it  is  necessary  that 
some  means  should  be  resorted  to  of  preserving  it  from  be- 
coming rancid,  and  this  is  done  by  salting  it. 

The  choice  of  a  kind  of  salt  suitable  for  preserving  but- 
ter is  not  a  matter  of  less  importance,  than  when  it  is  used 
for  salting  meat.  Only  such  should  be  used  as  has,  by  long 
exposure  upon  the  edges  of  the  salt-pans,  lost  all  the  deli- 
quescent salts  which  combined  with  it ;  salt  in  this  state  -is 
drier  and  purer,  than  the  new  salts  extracted  by  evaporation 
from  sea-water,  and  has  neither  the  sharpness  nor  the  bit- 
terness which  characterize  these.  But  whatever  salt  is 
used,  it  is  advisable  that  it  be  whitened  and  purified  by  the 
process  commonly  made  use  of  in  our  kitchens ;  it  must  be 
dried  in  an  oven,  and  afterwards  pounded  in  a  marble  or 
wooden  mortar. 

Nothing  more  is  requisite  in  salting  butter,  than  to  work 
it  well,  so  that  the  salt  may  be  equally  distributed,  and  then 
to  put  it  down  in  clean  and  dry  stone  jars.  If  it  should  be 
perceived,  seven  or  eight  days  after,  that  the  butter  has 
shrunk  so  as  to  leave  a  vacancy  around  the  sides  of  the 
pot,  a  brine  must  be  prepared  by  saturating  hot  water  with 
pure  salt,  and  this  when  cold  must  be  turned  gradually 
upon  the  butter  till  every   part  of  it  is  well  covered :    the 


OF  MILK  AND  ITS  PRODUCTS.  207 

pots  are  then  to  be  set  in  a  cool  place  till  the  butter  is  taken 
out  and  made  into  lumps  for  market  or  home  consumption. 

Another  way  in  which  butter  may  be  preserved  a  long 
time,  is,  by  melting  it  in  a  pot  at  a  very  low  degree  of  heat, 
skimming  from  the  surface  a  thin  layer  of  curd  which  will 
form  upon  it,  and  when  this  no  longer  collects,  withdrawing 
it  to  cool  and  harden. 

When  the  juices  of  fruits  are  to  be  preserved  for  food, 
sugar  is  used  instead  of  salt ;  this  possesses  the  double  ad- 
vantage of  correcting  the  acid  of  fruits,  and  of  incorpo- 
rating better  with  them.  Sugar  improves  the  quality  of  the 
juices  as  much  as  salt  would  injure  them,  and  as  this  last 
cannot  be  extracted,  they  could  not  be  used  as  articles  of 
nourishment. 

The  preparations  formed  with  sugar  are  jellies  and  sirups  ; 
the  first  are  the  most  concentrated,  and  serve  as  food ;  the 
latter  mix  easily  with  water,  and  are  generally  employed  as 
drinks. 

After  the  juices  are  expressed,  clarified,  and  strained, 
there  must  be  added  to  them  a  suitable  portion  of  sugar  : 
most  of  them  require  an  equal  weight :  they  must  then  be 
boiled  gently  till  sufficiently  evaporated,  and  the  operation 
completed  by  clarifying  the  liquor,  which  is  thus  rendered 
more  agreeable  to  the  eye. 


CHAPTER    XL 

OF    MILK    AND    ITS    PRODUCTS. 


There  is  no  product  of  a  farm  which  contributes  more 
towards  the  prosperity  of  the  establishment  than  milk; 
not  only  does  it  form  in  itself  one  of  the  most  important 
articles  of  food  for  the  family,  but  the  sale  of  a  portion  of 
it,  either  in  its  natural  state,  or  made  into  butter  or  cheese, 
furnishes  a  daily  income,  from  which  nearly  all  the  inter- 
nal wants  of  a  household  may  be  supplied  :  I  therefore 
think  it  will  not  be  departing  from  my  subject  to  devote 
one  chapter  in  this  work  to  an  object  of  so  much  impor- 
tance. Milk  appears  to  me  to  be  one  of  the  least  animal- 
ized  portions  of  the  animal  kingdom.  The  various  kinds, 
of  food  taken  by  animals  affording  milk,  give  to  it  various 


208  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

degrees  of  richness  and  different  tastes  :  the  milk  of  a  cow 
which  is  fed  upon  the  leaves  and  stalks  of  maize,  or  upon 
the  refuse  of  beets,  is  very  sweet,  and  that  of  a  cow  nour- 
ished with  cabbages  has  not  so  sweet  a  taste,  and  exhales  a 
disagreeable  odor  ;  the  milk  of  cows  which  browse  damp 
meadows  is  watery  and  insipid  :  from  these  facts  we  may 
establish  as  a  principle,  that  the  quality  of  milk  may  be  so 
varied  by  the  choice  of  food,  as  to  adapt  it  to  the  wants  of 
the  individual  to  be  nourished  by  it,  whether  he  be  a  healthy 
man  or  an  invalid. 

The  numerous  experiments  that  have  been  made  by  Messrs. 
Deyena  and  Parmentier  to  ascertain  the  effect  of  food  upon 
the  milk  of  a  cow,  furnish  the  following  results  : 

1st.  That  it  is  improper  to  change  suddenly  the  kind  of 
food,  as  it  for  a  time  diminishes  the  quantity  of  milk,  even 
though  the  food  be  more  succulent  and  of  a  better  kind. 

2nd.  That  all  plants  do  not  give  to  milk  their  characteris- 
tic qualities,  and  that  there  are  some  that  do  not  exercise 
any  particular  action  upon  either  of  the  c(Mistituent  princi- 
ples of  milk. 

By  distilling  milk  in  a  water-bath  there  is  obtained  an  ex- 
tract of  limpid  liquor  of  about  ^  the  weight  of  the  milk  em- 
ployed, having  the  odor  peculiar  to  milk,  and  containing  a 
putrefiable  animal  substance  which  gradually  renders  the 
color  of  the  extract  cloudy,  and  its  consistence  viscid ;  this 
substance  becomes  putrescent  in  a  longer  or  shorter  time, 
according  to  the  nature  of  the  food  upon  which  the  animal 
affording  the  milk  is  nourished. 

This  first  distillation  does  not  change  the  nature  of  the 
constituent  principles  of  milk;  they  remain  in  an  oily  mass 
of  a  sweetish  taste,  and  a  yellowish  white  color. 

Butter  and  cheese  are  the  two  principal  elements  of  which 
milk  is  composed  ;  the  cream  which  is  separated  from  the 
milk,  and  from  which  a  most  profitable  product  is  obtained, 
contains  only  one  of  them,  butter,  which  is  the  most  impor- 
tant part  of  the  cream,  and  is  obtained  from  it  by  a  very  sim- 
ple process :  the  whey  which  remains  after  the  butter  and 
cheese  have  been  separated  from  the  cream,  contains  in  so- 
lution some  salts,  and  serves  as  a  vehicle  or  dissolvent  for 
all  the  constituent  principles  of  milk. 

The  principles  contained  in  milk  are  not  united  by  a  pow- 
erful affinity ;  when  milk  is  allowed  to  remain  at  rest,  the 
butter  becomes  disengaged  and  rises  to  the  top,  where  it 
forms  a  layer  in  which  it  is  found  mixed  with  some  milk  j 


CREAM.  S09 

it  is  this  layer  which  is  known  under  the  name  of  cream. 
In  this  state  the  particles  of  butter  have  but  a  feeble  cohe- 
sion, and  still  retain  in  combination  a  portion  of  milk  which 
is  by  churning  completely  separated  from  them,  when  they 
appear  with  all  their  characteristic  qualities. 

As  the  preparation  of  these  two  products  of  the  same  fluid 
present  different  phenomena,  I  think  it  best  to  treat  of  them 
under  different  heads. 


ARTICLE    I. 
Of  Cream. 


The  surface  of  milk  which  is  allowed  to  remain  undis- 
turbed in  a  cool  place,  becomes  covered  with  a  thick,  unc- 
tuous substance  of  an  agreeable  taste,  and  usually  of  a 
yellowish  white  color ;  this  substance  is  called  cream.  The 
first  layer  which  is  formed  is  not  very  close,  but  as  the  but- 
ter ascends,  the  coat  increases  in  density ;  when  it  can,  by 
pressing  it  with  the  finger,  be  removed  without  disturbing 
the  milk,  it  is  time  for  it  to  be  skimmed  off.  Twenty-four 
hours,  with  a  degree  of  temperature  equal  to  59°  of  Fahren- 
heit's thermometer,  is  sufficient  for  raising  the  cream  :  but 
at  a  higher  temperature  the  cream  forms  more  quickly,  and 
has  less  consistency  ;  it  may  then  be  removed  in  twelve 
hours.  Cream  is  much  better  either  to  be  used  in  that  state, 
or  for  churning,  than  when  it  is  allowed  to  remain  a  longer 
time  upon  the  milk. 

Cream  should  be  kept  in  a  cool  place,  and  in  jars  with 
narrow  openings  closely  covered,  so  as  to  exclude  the  air,  and 
to  keep  it  from  being  affected  by  the  variations  of  tempera- 
ture in  the  atmosphere. 

From  experiments  recently  made,  we  ascertain,  that  the 
larger  the  surface  presented  to  the  air  by  milk  is,  the  more 
rapidly  is  the  cream  separated,  and  that  a  degree  of  heat 
equal  to  from  50°  to  55°  Fahrenheit,  is  the  most  favorable 
to  this  separation. 

As  the  abundance  and  the  quality  of  cream  depend  almost 
entirely  upon  that  of  the  butter,  which  constitutes  nearly  the 
whole  of  it,  I  shall  refer  to  the  following  article  the  remain- 
der of  what  I  have  to  say  upon  this  subject. 
18* 


210  CHYMISTKY    APPLIED    TO    AGRICULTURE- 

ARTICLE      11. 

Of  Butter, 

I  HAVE  already  remarked,  that  there  exists  between  the 
Gonstituent  principles  of  milk  but  a  very  feeble  affinity: 
rest  alone  is  sufficient  to  produce  the  separation  of  them 
in  the  course  of  a  few  hours,  when  the  butter  which  exists 
in  very  minute  particles  in  the  milk,  rises  to  the  surface  with- 
out any  approach  towards  forming  a  solid  body.  In  order  to 
bring  butter  into  a  solid  state,  it  is  necessary  to  disengage 
from  it  all  the  other  principles  which  it  carries  with  it :  this 
is  done  by  means  of  churning. 

It  has  been  clearly  proved  that  the  quantity  of  butter  pro- 
duced from  the  milk  of  a  new  milch  cow,  is  less  than  is 
yielded  by  the  niilk  of  the  same  cow  five  or  six  months  after 
calving.  It  is  likewise  well  known,  that  if  cream  be  re- 
moved as  fast  as  it  is  formed,  the  butter  made  from  the  first 
layers  will  be  more  delicate  than  that  from  the  last.  Milk 
that  has  remained  a  long  time  in  the  udder,  furnishes  more 
butter  than  that  which  is  drawn  as  soon  as  it  is  secreted : 
thus  milk  that  is  drawn  from  a  cow  but  once  a  day,  will  yield 
one  seventh  more  of  butter. 

Milk  obtained  at  the  same  milking  presents  similar  differ- 
ences ;  the  portion  which  is  drawn  first,  is  thinner  and  more 
watery  than  the  last  drawn,  and  it  yields  less  butter. 

All  these  facts,,  ascertained  by  experiment,  are  capable 
of  being  extensively  applied  both  in  medicine  and  rural 
economy. 

The  particles  of  butter  contained  in  cream,  cannot  be 
separated  from  the  milky  portions  with  equal  ease,  at  all 
seasons  of  the  year,  or  at  all  degrees  of  temperature ;  the 
operation  of  churning  requires  much  m.ore  time  in  winter 
than  in  summer,  nor  can  the  process  be  shortened  except- 
ing by  enveloping  the  churn  in  a  hot  cloth,  or  by  plunging  it 
into  hot  water  ;  hot  milk  is  sometimes  added  to  the  cream  ; 
but  all  these  means  affect  more  or  less  the  good  qualities  of 
the  butter. 

During  the  heat  of  summer,  it  is  necessary  to  set  the  cream 
in  a  cool  place,  and  to  churn  at  those  hours  of  the  day  that 
are  coolest ;  in  some  countries,  it  is  customary  to  place  the 
churn  in  very  cold  water. 

The  butter  made  in  some  countries,  and  which  is  thought 


BUTTER.  211 

to  be  of  the  best  kind,  is  yellow,  and,  to  deceive  consumers, 
artificial  means  are  had  recourse  to  elsewhere,  to  give  this 
product  the  same  appearance.  For  this  purpose  the  flowers 
of  the  marigold  are  put  into  stone  pots,  where  they  are  allow- 
ed to  macerate  for  several  months,  till  a  thick  liquor  is 
formed ;  this  is  strained  through  a  cloth,  and  set  by  for  use. 
Saffron  flowers,  roucou  (annotto)  boiled  in  water,  the  juice 
of  yellow  carrots,  &,c.  are  employed  for  the  same  purpose. 
Whatever  coloring  matter  is  made  use  of,  it  is  put  into 
the  cream  before  churning,  and  in  so  small  a  quantity  as  not 
to  influence,  in  any  degree,  the  taste  or  wholesomenessof  the 
butter. 

The  milk  of  all  the  various  animals  that  has  been  subject- 
ed to  experiment,  contains  the  same  principles ;  there  is  found 
no  difterence  excepting  in  the  proportion,  consistency,  and 
quality  of  the  products. 

The  principles  contained  in  milk  are  more  easily  separa- 
ted in  that  of  the  cow,  than  in  that  of  any  other  animal,  and 
it  is  of  this  that  the  greatest  use  is  made  both  for  butter  and 
cheese. 

The  milk  of  the  sheep  furnishes  a  large  proportion  of  but- 
ter, but  it  nevier  has  the  consistency  of  that  from  cows'  milk ; 
it  is  oily,  and,  unless  very  carefully  washed,  soon  becomes 
rancid ;  it  is  more  easily  melted  than  the  butter  from  cows' 
milk.  It  is  difficult  to  curdle  this  milk  ;  the  caseous  mat- 
ter remains  always  in  a  viscous  state ;  its  taste  is  sweet 
and  agreeable. 

Goats'  milk  has  more  consistency  than  cows'  milk ;  it  is 
distinguished  by  a  peculiar  odor,  especially  at  certain  sea- 
sons :  the  cream  which  rises  upon  this  milk  is  always  very 
thick,  and  the  butter  made  from  it  is  uniformly  white.  It 
may  be  kept  free  from  alteration  a  longer  time  than  other 
milk  :  it  is  richer  in  caseous  matter  than  any,  excepting  that 
of  the  sheep,  but  contains  less  butter  than  either  cows'  or 
sheep's  milk.  The  slightly  viscous  character  of  the  caseous 
matter,  and  its  peculiar  taste,  render  it  excellent  for  making 
cheese. 

There  is  no  kind  of  milk,  of  which  different  examinations 
of  the  products  afford  such  different  results,  as  that  of  wo- 
man :  not  only  does  the  milk  of  different  individuals  present 
very  different  results,  but  that  of  the  same  nurse,  when  an- 
alyzed at  various  times,  offers  unlike  proportions  of  the  prin- 
ciples :  this  has  been  ascertained  by  the  experiments  of 
Messrs.  Deyeux  and  Parmentier.     This  milk,  like  any  other, 


212  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

becomes  covered  with  a  coat  of  cream,  but  it  is  often  the 
ease,  that  the  most  prolonged  churning  cannot  produce  any 
butter  from  it.  Repeated  experiments  have  proved,  that  the 
caseous  matter  in  this  kind  of  milk  increases  with  the  lapse 
of  time  from  the  lying  in ;  and  that  this  is  so  feebly  dissolved, 
as  to  become  separated  into  very  finely  divided  molecules'  at 
a  temperature  of  68°  Fahrenheit :  this  substance  has  always 
some  viscosity,  and  is  never  dry  and  quivering  like  that  of 
cows'  milk. 

The  astonishing  differences  which  appear  in  woman's 
milk  may  be  attributed  to  the  passions  of  the  mind,  to  ner- 
vous agitation,  and  to  frequent  changes  of  diet.  The  action 
of  the  two  first  agents  is  of  the  most  powerful  kind,  and  as 
they  are  exercised  most  vigorously  and  frequently  upon  the 
human  species,  it  is  not  astonishing  that  they  should  exert  a 
decided  influence  upon  the  milk  of  women.  These  observa- 
tions deserve  great  attention  from  all  who  are  interested  in 
nursing  children. 

The  milk  of  the  ass  bears  a  strong  resemblance  to  that  of 
woman;  it  throws  up  a  cream  which  is  neither  thick  nor 
abundant,  and  from  which  there  may  be  extracted,  though 
not  without  difficulty,  a  small  quantity  of  soft,  insipid,  white 
butter,  which  easily  becomes  rancid. 

Neither  woman's  nor  asses'  milk  affords  so  much  caseous 
matter  as  that  of  the  cow  or  sheep ;  what  is  obtained  is  more 
viscous,  and  possesses  but  a  slight  degree  of  adherence  to 
the  serum.  The  resemblance  of  asses'  milk  to  that  of  wo- 
man has  caused  it  to  be  used  in  those  cases,  where  it  was 
necessary  to  employ  a  mild  diet.  It  possesses  the  advantage 
over  the  last,  of  not  varying  so  much  in  its  quality  and  con- 
sequently in  its  effects. 

The  fluidity  of  mare's  milk  is  less  than  of  the  two  last- 
mentioned  kinds,  and  its  taste  is  less  sweet ;  it  furnishes 
some  cream,  but  it  is  difficult  to  procure  butter  from  it ;  it 
contains  but  little  caseous  matter,  and  in  all  its  products 
bears  a  resemblance  to  the  milk  of  the  human  female  and 
of  the  ass. 

From  the  foregoing  statement  we  perceive  that  the  ru- 
minating animals  afford  similar  kinds  of  milk,  and  that 
this  milk  possesses  peculiar  and  distinguishing  charac- 
teristics :  all  the  kinds  contain  the  same  principles,  but 
these  principles  vary  in  proportion,  quantity,  consistency, 
and  taste. 

The  difference  existing   amongst  the   several  kinds  of 


BUTTER.  21^ 

milk  greatly  influences  the  products  obtained  from  them ; 
but  if  they  be  rightly  mixed  together,  the  qualities  of  one 
kind  may  serve  to  correct  the  faults  of  another,  and  thus 
more  valuable  products  may  be  procured  from  the  combi- 
nation of  two  or  more  kinds  than  could  be  had  from  either 
separately. 

The  process  of  churning  unites  into  one  mass  all  the 
particles  held  in  solution  by  milk,  and  brought  into  a  some- 
what more  condensed  state  in  cream ;  but  there  still  exist 
in  butter  some  milky  particles,  which  cause  it  to  undergo 
a  change  :  to  avoid  this,  it  is  necessary  to  free  the  butter 
carefully  from  milk.  When  butter  is  made  from  fresh 
cream,  and  is  to  be  immediately  consumed,  nothing  more 
is  done  to  it  than  to  work  it  over  carefully  with  the  hand, 
till  all  the  milk  is  expressed  from  it ,  it  then  retains  all  the 
sweet  and  agreeable  flavor  of  cream  :  but  when  it  is  to  be 
kept  for  any  length  of  time,  it  is  necessary  that  it  should  be 
kneaded  with  cold  water,  till  the  liquid  runs  off  free  from 
milkihess. 

All  the  operations  required  to  bring  cream  into  complete- 
ly-made butter,  should  succeed  each  other  without  delay  ; 
for  the  milk  expressed  from  butter  made  of  cream  which 
has  remained  too  long  a  time  upon  milk,  or  in  the  churn,  has 
a  vinous  taste. 

The  less  care  there  is  taken  to  free  butter  from  the  butter- 
milk, the  sooner  will  it  become  rancid ;  in  order  therefore 
to  preserve  to  it  all  the  qualities  of  fresh  butter,  it  should  be 
carefully  washed  and  kneaded :  it  must  likewise  be  kept  in 
a  cool  place,  or  under  cold  water  that  can  be  frequently 
changed :  it  is  sometimes  melted  at  a  low  temperature,  and 
allowed  to  remain  in  this  state  till  all  the  watery  particles 
contained  in  it  are  evaporated.  I  have,  in  a  former  place, 
spoken  of  the  method  of  salting  butter ;  this  is  the  surest 
means  of  preserving  it.     (See  Chap.  X.) 

According  to  the  experiments  of  Messrs.  Deyeux  and  Par- 
mentier,  the  rancidity  of  butter  arises  from  its  combining 
with  oxygen  when  exposed  in  contact  with  the  air  :  butter 
absorbs  about  -^  of  its  volume  of  oxygen,  and  acquires  from 
the  union  a  strong,  acrid,  disagreeable  taste. 


214  CHYMISTRY   APPLIED   TO    AGRICULTURE. 

ARTICLE    III. 
Of  Caseous  Matter. 

When  milk  has  been  skimmed,  if  it  be  afterwards  heat- 
ed to  any  degree  short  of  ebullition,  there  form  upon  the 
surface  pellicles  which  gradually  acquire  some  degree  of 
consistency,  and  which  may  be  easily  removed  :  by  con- 
tinuing the  heat  these  may  be  renewed,  till  at  length  the 
milk  can  furnish  no  more  of  them  :  in  this  state  milk  can 
be  boiled  without  occasioning  any  of  that  violent  swelling 
and  rising  which  is  so  hard  to  check,  and  which  causes 
the  boiling  of  this  liquid  to  be  so  troublesome  ;  but  then  it 
will  contain  neither  butter  nor  caseous  matter  :  the  butter 
has  been  separated  in  removing  the  cream,  and  the  pelli- 
cles are  the  caseous  matter :  what  remains  after  these  two 
operations  is  only  whey,  holding  in  solution  some  known 
salts. 

I  have  already  remarked,  that  these  pellicles  form  only  in 
contact  with  the  air  ;  they  do  not  appear  when  milk  is  boil- 
ed in  closely-corked  bottles  :  the  production  of  them  may  be 
accelerated  by  the  passage  of  a  current  of  air  over  the  sur- 
face of  the  milk. 

The  caseous  matter  may  be  separated  from  skimmed  milk 
by  exposing  it  to  a  gentle  heat,  when  it  assumes  the  form  of 
a  soft,  quivering  mass ;  this  is  called  curd  :  two  or  three 
days'  exposure  to  a  heat  of  from  68°  to  77°  Fahrenheit  is 
sufficient  to  produce  this  effect. 

As.  the  caseous  "matter  adheres  but  slightly  to  the  serum, 
and  to  the  salts  which  are  contained  in  it,  it  can  be  sepa- 
rated by  means  of  a  great  variety  of  different  bodies :  it  is 
to  the  action  of  some  one  of  these  that  recourse  is  had  for 
coagulating  milk. 

Acids  of  all  kinds  coagulate  skimmed  milk  very  quickly ; 
the  change  takes  place  more  or  less  rapidly  according  to 
the  strength  of  the  acid  employed  ;  if  a  larger  quantity  be 
used,  the  curd  is  injured  by  retaining  the  taste  of  the  acid. 

The  salts  which  contain  an  excess  of  acid,  as  the  cream 
of  tartar,  and  the  salts  of  sorrel,  produce  the  same  effects, 
but  the  coagulation  is  not  complete  unless  the  milk  is  near 
boiling  when  the  salts  are  thrown  into  it. 

The  rapidity  with  which  the  sulphates  coagulate  milk  is 
very  remarkable  :  the  action  of  these  is  most  energetic  upon 
boiling  milk. 


CASEOUS    MATTER.  215 

Alcohol  speedily  precipitates  the  caseous  matter  under 
the  form  of  fine  molecules,  at  the  bottom  of  the  vessel. 

Very  acid  plants  and  the  flowers  of  some  vegetables, 
such  as  the  artichoke  and  the  thistle,  curdle  milk  :  these 
are  usually  employed  by  infusing  them  in  cold  water,  and 
their  action  upon  warm  milk  is  very  powerful. 

The  substance  however  which  is  most  generally  used  is 
a  portion  of  the  milk  curd  which  is  found  in  the  stomachs 
of  young  calves  that  have  been  killed  before  they  were 
weaned.  The  use  which  is  made  of  this  substance  has 
given  it  the  name  of  rennet*  This  substance  is  prepared 
for  use  in  the  following  manner.  The  membrane  of  the 
stomach  of  a  young  and  newly  killed  animal  is  opened,  and 
the  coagulated  milk  is  taken  out,  washed  with  cold  water, 
dried  with  a  linen  cloth,  salted,  and  returned  into  the  mem- 
brane ;  this  is  suspended  in  a  dry  place  that  the  rennet 
may  be  freed  from  moisture  :  the  rennet  may  afterwards  be 
used  by  mixing  a  little  of  it  in  milk,  and  then  throwing  the 
liquid  into  the  milk  which  is  to  be  curdled. 

The  quantity  of  rennet  necessary  to  be  employed  at  any 
one  time  for  the  same  measure  of  milk,  varies  very  much 
according  to  the  quality  of  the  milk  and  the  temperature  of 
the  atmosphere  :  thick,  rich  milk,  which  has  not  been  skim- 
med, requires  more  than  that  which  is  thin,  or  from  which 
the  cream  has  been  removed.  In  winter  it  is  often  neces- 
sary to  warm  milk  slightly  to  make  it  curdle. 

As  soon  as  the  milk  curdles  it  is  allowed  to  remain  un- 
disturbed in  a  cool  place,  in  order  that  the  curd  may  ac- 
quire some  degree  of  firmness,  and  that  all  the  particles  may 
become  united  in  one  mass,  and  likewise  to  allow  all  the 
whey  to  drain  off:  it  is  then  dipped  up  with  a  skimmer 
and  put  into  a  vat  or  bucket  of  osier,  through  which  the 
whey  contained  in  the  curd  can  escape  freely.  As  soon 
as  the  curd  has  acquired  a  certain  degree  of  consistency 
in  the  willow  baskets,  it  is  removed  into  vats  of  earthen- 
ware having  small  holes  in  the  bottom  ;  through  these  the 
whey  still  continues  to  drop,  and  the  curd  gradually  in- 
creases in  density.  Cuid,  from  its  first  formation  to  the 
period  of  which  we  are  now  speaking,  forms  an  article  of 
diet  equally  healthy  and  agreeable,  and  furnishes  a  great 


rin  this  country  the  term  is  applied  to  the  dried  and  salted  stom- 
of  the  calf,  a  piece  of  which  is  employed  to  produce  the  coagula- 
tion required. — Tr.] 


216  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

resource  for  variety  in  the  food  of  the  inhabitants  of  the 
country.  But  as  these  preparations  cannot  be  preserved  for 
any  length  of  time,  it  is  necessary  to  find  some  means  of 
keeping  them  free  from  alteration,  or  so  to  moderate  and 
govern  decomposition,  that  the  food  furnished  by  the  case- 
ous matter  may  be  varied,  and  the  power  of  keeping  it  pro- 
longed :  this  object  is  obtained  in  the  fabrication  of  cheese. 

The  existence  of  whey  in  curd  hastens  most  powerfully 
the  action  of  putrid  decomposition ;  and,  in  order  to  pre- 
vent or  retard  this  change,  it  is  necessary  that  the  whey 
be  forced  out  by  mechanical  power.  Those  cheeses  which 
are  the  best  dried,  may  be  preserved  the  longest  time  ;  in 
order  to  hasten  the  drying,  the  curd  is  carefully  kneaded, 
and  in  some  cases  the  cheese  is  exposed  to  heat  or  to  a 
strong  pressure. 

The  period  during  which  cheeses  can  be  kept  may  be 
prolonged,  by  impregnating  them  well  with  salt ;  this  is 
done  in  the  following  manner :  when  the  curd  has  ac- 
quired the  requisite  degree  of  consistency,  the  surface  of 
it  is  furrowed  and  covered  with  pounded  salt ;  the  next 
day  the  cheese  is  turned,  and  the  same  operation  perform- 
ed upon  the  other  side  of  it.  This  salting  is  repeated  till 
every  part  of  the  cheese  is  well  seasoned,  it  is  then  placed 
upon  a  bed  of  straw,  and  turned  from  time  to  time.  The 
straw  upon  which  cheeses  are  placed,  must  be  frequently 
changed,  and  the  planks  washed,  and  in  every  part  of  a 
dairy  the  greatest  cleanliness  and  neatness  should  be  ob- 
served. 

The  surface  of  a  new  cheese  gradually  loses  its  white 
appearance  under  the  above  treatment;  the  size  is  diminished, 
and  there  is  formed  an  external  crust  harder  than  the  middle, 
and  having  a  sharper  and  less  agreeable  taste. 

When  the  caseous  matter  is  precipitated  from  milk  re- 
taining its  cream,  the  cheeses  formed  from  it  are  not  so 
dry  as  those  which  consist  entirely  of  the  caseous  part  ; 
their  taste  is  mild  and  their  substance  more  mellow  and 
unctuous. 

Independently  of  the  modifications  which  cheese  is  sus- 
ceptible of,  from  the  addition  or  suppression  of  cream,  the 
mixture  of  different  kinds  of  milk  varies  it  greatly.  I  for- . 
merly  remarked  that  the  milk  of  the  sheep  and  goat  was 
softer  and  more  viscous  than  that  of  the  cow  ;  this  renders 
the  cheese  made  from  it  mellow,  besides  its  possessing  a 
very  agreeable  flavor.     The  most  celebrated  cheeses  are 


CASEOUS    MATTER.  217 

made  from  a  mixture  of  cows'  milk  with  the  milk  of  sheep 
or  goats. 

I  will  here  give  a  hasty  sketch  of  the  most  usual  pro- 
cesses by  which  cheese  is  made. 

When  the  curd  has  been  deprived  of  its  whey,  except- 
ing what  may  ooze  from  it  in  the  vats  or  upon  the  straw,  it 
undergoes  various  degrees  of  decomposition,  which  at  differ- 
ent periods  furnish  several  kinds  of  food. 

A  new  or  white  cheese  gradually  shrinks,  and  its  surface 
becomes  covered  with  a  crust  or  rind,  whilst  the  interior 
preserves  more  of  its  softness  :  at  the  end  of  some  time  fer- 
mentation takes  place,  when  it  exhales  an  odor  which  be- 
comes more  and  more  sharp  ;  a  similar  change  likewise 
takes  place  in  the  taste :  this  stage  of  decomposition  is  the 
most  favorable  for  disposing  of  white  cheese. 

When  cows'  milk  that  has  been  skimmed  is  used  for 
cheese,  the  article  produced  from  it  is  always  dry  ;  but  if 
the  curd  be  formed  from  milk  retaining  the  cream,  the  curd 
contains,  in  addition  to  the  caseous  matter,  all  the  princi- 
ples of  the  cream  ;  and,  when  treated  in  the  usual  manner, 
a  white  cheese  is  obtained  from  it  which  is  not  slow  in 
changing  its  consistence  :  the  interior  of  such  a  cheese 
softens  and  takes  the  form  and  nearly  all  the  character  of 
cream.  Cheese  in  this  state  is  delicious  to  the  palate  ;  but 
it  soon  undergoes  a  putrid  decomposition  which  changes  its 
quality. 

There  is  a  very  delicate  and  much  sought  for  prepara- 
tion, which  is  improperly  called  cheese  ;  this  is  made  by 
churning  fresh  cream  till  it  has  acquired  a  degree  of  con- 
sistency, without  the  butter's  being  separated  from  it. 

All  kinds  of  cheese  cannot  be  kept  good  a  long  time ; 
but  if  the  curd  be  strongly  pressed  so  as  to  extract  all  the 
whey,  and  afterwards  carefully  salted,  cheeses  may  be 
made  of  it  which  can  be  preserved  a  considerable  length 
of  time.  To  effbct  this,  the  curd  is  divided  with  a  wooden 
knife,  kneaded,  and  squeezed  with  the  hands  ;  and  when 
all  parts  of  it  have  been  well  worked,  it  is  put  to  drain. 
As  soon  as  the  whey  has  ceased  to  drop  from  it,  it  is  again 
kneaded  and  submitted  to  a  considerable  pressure,  by 
which  all  the  liquid  particles  which  can  be  extracted  from 
it,  are  forced  out. 

When  the  curd  has  by  these  operations  been  brought  to 
a  due  degree  of  dryness,  it  is  salted  :   this  is  done  by  again 
carefiilly  kneading  the   curd  and    afterwards   breaking   it 
19 


218  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

into  pieces,  into  each  of  which  the  salt  is  worked  by  the 
hand  ;  a  mould  or  form  is  then  filled  with  the  curd ;  this 
is  covered  over  with  a  cloth,  upon  which  is  placed  a  weight 
to  press  the  cheese  ;  by  this  process  the  salt  is  made  to 
penetrate  the  whole  mass,  and  the  last  remaining  portions 
of  whey  are  forced  out. 

The  whey  which  is  disengaged  by  this  last  operation  is 
very  salt,  and  is  usually  preserved  to  moisten  cheeses  with, 
when  by  their  progress  of  decomposition  they  have  become 
too  dry. 

The  curd  remains  under  the  press  several  days,  and  is 
turned  from  tim,e  to  time,  that  the  salt  may  become  incor- 
porated with  the  mass,  and  that  the  whey  may  be  perfectly 
separated  from  it. 

When  the  cheese  is  taken  from  the  press  it  is  placed  in 
a  situation  where  the  temperature  is  cool  and  equal,  and 
where  it  will  not  be  exposed  to  light  or  insects,  and  there 
it  undergoes  the  other  processes,  by  which  the  making  of 
a  cheese  is  completed.  These  processes  vary  much  in 
different  places  :  in  some  a  cheese  is  turned  every  day, 
and  its  surface,  as  soon  as  it  becomes  dry,  is  moistened  with 
salted  whey  ;  if  a  cheese  becomes  mouldy,  the  rind  is  for- 
cibly scraped  with  a  wooden  knife;  in  other  places  the 
rind  is  scraped  and  taken  off  every  five  or  six  days,  and 
by  this  means  the  part  that  is  most  advanced  in  decompo- 
sition, is  removed  and  sold  at  a  low  price  to  the  people. 
As  soon  as  this  crust  is  taken  off,  the  new  surface  is  rubbed 
with  salt,  which  is  forced  into  it  with  the  hand ;  the  cheese 
is  then  carried  into  the  cellar  :  the  operation  is  repeated  till 
the  cheese  is  disposed  of 

If,  in  drying  the  curd,  the  action  of  fire  is  added  to  com- 
pression, a  firmer,  harder  cheese,  and  one  of  very  different 
qualities,  is  obtained  :  a  cheese  prepared  in  this  way  can  be 
kept  a  longer  time  than  others. 

In  the  manufacture  of  this  kind  of  cheese,  the  milk  is 
placed  in  a  boiler  over  a  moderate  fire,  and  the  necessary 
quantity  of  rennet  is  stirred  carefully  into  it :  as  soon  as 
the  rennet  begins  to  affect  the  milk,  it  is  removed  from  the 
fire,  when  the  curd  very  soon  acquires  some  degree  of  so- 
lidity :  all  the  whey  which  can  in  this  state  be  extracted 
from  it,  is  removed,  and  the  boiler  again  placed  upon  the 
ire  ;  the  curd  is  constantly  stirred  either  by  the  hand  or 
with  a  slip  of  wood :  this  operation  is  continued,  till  the 
dots  which  swim  in  the  whey^  which  is  expressed  from 


CASEOUS    MATTER,  ^19 

them,  have  acquired  so  much  firmness,  as  to  resist  the! 
pressure  of  the  finger,  and  present  a  yellow  appearance  : 
the  boiler  is  now  taken  from  the  fire,  and  the  stirring  and 
squeezing  continued,  till  the  curd  is  cool,  when  it  is  put 
into  a  mould  and  submitted  to  a  strong  pressure  to  extract 
all  the  remaining  serum. 

After  these  first  operations  are  completed,  the  curd  is 
again  kneaded,  in  order  to  give  it  the  different  forms  un- 
der which  this  kind  of  cheese  is  known  in  commerce. 
The  cheeses  when  formed,  are  rubbed  over  with  salt ;  this 
is  repeated  every  day,  and  the  cheeses  are  at  the  same 
time  turned  ;  the  salting  is  completed  when  the  surfaces 
exhibit  a  superabundance  of  moisture,  as  this  announces 
the  cheeses  to  be  saturated  with  salt.  The  cheeses  are 
then  put  into  a  cool  place,  where  they  will  be  safe  from 
insects. 

In  general,  cheeses  made  in  this  way  are  hard  and  dry,  and 
may  be  kept  a  long  time  :  the  nature  of  the  caseous  mat- 
ter of  cow's  milk,  from  which  they  are  prepared,  contrib- 
utes not  a  little  to  these  qualities. 

There  is  no  food  made  use  of  by  man  which  presents  so 
great  a  variety  as  does  cheese ;  this  arises  from  some  cir- 
cumstances of  which  we  can  ascertain  the  causes. 

The  milk  which  is  furnished  by  animals  of  different 
kinds,  is  not  of  the  same  quality,  and  consequently  the 
butter  and  caseous  matter  obtained  from  it  are  very  dis- 
similar, and  the  cheese  made  from  sheeps'  or  goats'  milk 
is  much  more  mellow  and  agreeable  than  that  from  cows' 
milk. 

The  milk  of  animals  of  the  same  kind  varies  very  much 
with  the  health,  the  food,  season  of  the  year,  length  of 
time  from  bringing  forth  young,  &c. ;  all  these  circum- 
stances modify  the  quality  of  this  secretion  indefinitely. 

The  mixture  of  milk  obtained  at  different  times,  during 
a  space  of  several  days,  the  quality  and  proportion  of  the 
rennet  employed,  the  temperature  of  the  weather,  and  the 
calm  or  stormy  state  of  the  atmosphere,  the  cleanliness  of 
the  dairy,  and  of  the  utensils  employed,  the  degree  of  care 
with  which  the  curd  is  freed  from  whey,  the  choice  of  a 
proper  kind  of  salt  for  seasoning,  the  course  which  is  pur- 
sued in  governing  the  fermentation,  and  the  size  of  the 
cheese  upon  which  all  these  circumstances  operate,  com- 
bine to  influence  the  quality  of  the  product ;  and  however 
much  care  may  be  taken  in  the  various  parts  of  the  proces* 


220  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

of  cheese-making,  it  is  very  difficult  always  to  obtain  the 
same  results :  it  is  for  this  reason  that  we  seldom  have  two 
cheeses  precisely  alike  in  all  respects. 

The  custom  which  is  practised  in  some  countries,  of 
skimming  the  milk  before  forming  the  curd,  gives  to  the 
product  a  peculiar  character ;  such  cheeses  are  dry  and  very 
suitable  for  keeping  ;  they  may  be  made  of  very  great  size. 

By  mixing  the  milk  of  the  goat  or  sheep,  with  that  of 
the  cow,  cheeses  may  be  made  very  superior  to  those  ob- 
tained from  cows'  milk  alone  :  it  is  from  this  mixture  that 
the  two  best  kinds  of  French  cheese,  the  Roquefort  and 
the  Sassenage,  are  made  :  if  the  first  of  these  is  superior 
to  the  last,  it  is,  I  think,  owing  to  the  cellars  in  which  it 
is  prepared :  these  cellars  are  backed  by  a  rock  which 
presents  numerous  chinks  and  openings,  by  which  there 
constantly  escapes  a  rapid  current  of  air,  which  keeps  the 
temperature  but  4°  or  5°  Falirenheit  above  freezing  ;  *  the 
fermentation,  therefore,  is  very  slow,  and  may  be  regulated 
at  pleasure. 

Cheeses  made  entirely  of  goats*  milk  are  more  delicate 
than  those  made  partly  of  cows'  milk,  but  they  cannot 
easily  be  kept  for  any  length  of  time  ;  they  should  there- 
fore be  made  small,  and  be  eaten  as  soon  as  they  have  at- 
tained their  perfection. 

Much  cheese  is  made  in  France,  but,  with  the  exception 
of  five  or  six  places,  but  little  care  is  given  to  this  article, 
and  the  consumption  of  it  is  confined  to  the  vicinity  in 
which  it  is  fabricated.  None  of  our  cheeses  are  capable 
of  being  kept  any  great  length  of  time. 

The  importation  of  foreign  cheese  is  very  considerable  : 
it  is  desirable  that  extensive  establishments  should  be  formed, 
where  the  product  from  the  neighboring  dairy  farms  should 
be  brought  to  undergo  the  necessary  manipulations. 

The  manufactories  of  Roquefort  are  supplied  in  this 
manner  with  new  cheeses  bought  upon  the  mountains  of 
Larzac. 

The  successful  attempts  which  have  been  made  in  many 
parts  of  France,  to  imitate  the  cheeses  of  Holland,  Swit- 
zerland, and  England,  leave  no  doubt  in  regard  to  the 
possibility  of  introducing  this  valuable  branch  of  rural  in- 
dustry among  us. 

*  In  the  month  of  July,  1784,  my  thermometer  indicated  22°  (72^^ 
0      Fahr.)  in  the  external  air  ;  when  carried  into  these  cellars,  it  sunk  ta 
2°  (36°  Fahr.),  and  there  remained. 


AGRICULTURAL    AND    MANUFACTURING    NATIONS.        221 


CHAPTER  XIL 

COMPARISON    BETWEEN    AN   AGRICULTURAL    AND  A  MANUFAC- 
TURING   NATION. 

No  nation  in  Europe  can  be  called  purely  agricultural 
or  purely  manufacturing  ;  in  all,  these  characters  are  more 
or  less  united. 

But  when  a  nation  has  formed  within  itself  centres  of 
manufacturing  industry,  the  products  of  which  are  every- 
where diffused,  and  when  the  existence  of  a  large  portion 
of  its  inhabitants  essentially  depends  upon  the  prosperity 
of  its  manufacturing  establishments,  it  is  justly  styled  a 
manufacturing  nation ;  whilst  the  nation  which  exports  a 
large  proportion  of  the  products  of  its  soil,  and  has  only 
a  few  manufactures  to  supply  its  most  urgent  local  wants, 
is  an  agricultural  nation. 

Several  causes  conspire  in  establishing  thi&  distinction. 

A  nation  which  possesses  an  extensive  and  fertile  soil, 
capable  of  furnishing  occupation  to  its  whole  population, 
cannot  but  be  agricultural ;  but  if  its  population  exceed 
the  demands  of  agriculture,  there  must  necessarily  be 
either  an  emigration  of  a  part  of  it  to  other  countries,  as 
has  been  frequently  observed  in  the  north,  or  a  formation 
of  manufacturing  establishments  to  provide  them  with 
employment 

Whenever,  by  the  revolutions  which  have  so  frequently 
taken  place  in  Europe,  a  part  of  the  population  has  been 
forced  to  migrate  into  desert  countries,  of  an  almost  barren 
soil,  these  colonies  have  in  the  first  place  drawn  from  the 
soil,  by  labor,  all  that  it  was  able  to  furnish,  and  manufac- 
turing industry  has  then  become  a  powerful  auxiliary  to 
agriculture,  in  ensuring  them  a  subsistence.  The  popula- 
tion of  mountainous  countries  everywhere  affords  exam- 
ples in  support  of  these  principles. 

We  shall  even  observe  that  in  those  mountainous  coun- 
tries, where  the  frugality  of  the  inhabitants  makes  labor 
cheap,  manufacturing  industry  has  maintained  itself  and 
prospered,  until  machinery  has  superseded  manual  labor, 
and  made  it  an  insufficient  auxiliary  in  the  execution  of 
products. 

Manufactures  have  then  established  themselves  wherever 
science  and  the  mechanic  arts  have  made  the  greatest  pro- 
19* 


222  CHYMISTRY    APPLIED    TO   AGRICULTURE, 

gress,  and  France  and   England  have  divided  this  branch 
of  industry  between  them. 

France  was  already  in  possession,  almost  without  a  rival, 
of  manufactures  of  silks,  lawns,  cambrics,  laces,  fine  cloths, 
and  several  other  articles  essentially  connected  with  its 
agriculture  ;  but  England,  toward  the  middle  of  the  last 
century,  opened  a  branch  of  industry  in  the  cultivation  of 
which  she  has  enjoyed  a  high  superiority  till  the  present 
day, — that  of  the  spinning  and  weaving  of  cotton;  and, 
since  that  period,  she  has  carried  to  a  remarkable  degree 
of  perfection  all  other  kinds  of  manufactures. 

France  has  constantly  shown  herself  superior  in  the  ap- 
plication of  chymistry  to  the  arts;  England  in  the  con- 
struction and  employment  of  machinery.  ' 

The  application  of  the  sciences  to  manufacturing  opera- 
tions has  rendered  labor  more  regular,  more  prompt,  more 
economical  ;  the  fabrication  of  products  has  been  no  longer 
limited,  and  their  consumption  has  increased,  in  conse- 
quence of  their  superior  quality  and  low  price. 

But  has  this  great  revolution,  effected  in  manufacturing 
industry,  been  advantageous  to  the  human  race  1  It  has 
unquestionably  been  so  to  the  undertaker,  and  to  the  con- 
sumer ;   but  has  it  also  been  so  to  agriculture  ? 

Formerly,  almost  all  the  manufactured  articles  necessary 
to  the  inhabitants  of  the  country,  were  made  in  every  coun- 
try household,  and  whatever  was  not  needed  for  domestic 
use,  was  advantageously  sold  ;  to  this  labor  were  devoted 
the  long  winter  evenings,  and  all  the  time  not  required  for 
the  cultivation  of  the  soil.  The  low  price  to  which  the 
use  of  machinery  has  reduced  these  articles  no  longer 
permits  the  farmer  to  sustain  a  competition  in  price,  and  he 
finds  himself  deprived  of  a  resource  which  was  of  itself 
sufficient  to  pay  his  taxes  :  thus  agriculture  is  a  sufferer. 

These  large  manufacturing  centres  have  attracted  the 
inhabitants  of  the  country  by  the  offer  of  higher  wages  ;  but 
hardly  has  he  entered  the  establishment,  when  a  total 
change  takes  place  in  him  ;  he  is  no  longer  the  frugal  peas- 
ant ;  in  changing  labor,  diet,  and  society,  he  gradually  con- 
tracts new  habits  ;  his  health  is  affected,  and  the  human 
race  is  insensibly  deteriorated.  Should  a  stagnation  of  com- 
merce take  place,  he  is  thrown  out  of  employment,  and 
has  then  no  resource  but  in  public  compassion. 

These  inconveniences  are  carried  to^excess  in  England, 
where  the  vicissitudes  of  commerce  often  peril  the  exist- 
ence of  half  the  population,  and  cause  disorder  in  society. 


AGRICULTURAL    AND   MANUFACTURING   NATIONS.     223 

More  happy  than  England,  France  cannot  be  tormented 
by  these  fears.  In  a  population  of  from  thirty  to  thirty- 
two  millions,  the  proportion  of  those  possessing  no  propn 
erty,  is  hardly  one  sixth,  and  the  resources  which  agricul- 
ture presents  are  immense.  France  possesses  but  two 
great  manufacturing  centres,  Lyons  and  Rouen  ;  and  when 
the  operatives  there  are  out  of  employment,  they  disperse 
themselves  in  the  country,  where  they  find  occupation. 

Manufacturing  and  commercial  crises  are  less  numerous 
in  France  than  in  England,  and  there  are  two  principal 
reasons  of  this  difference :  the  first  is,  that  manufacturing 
is  carried  on  to  a  much  greater  extent  in  England  than  in 
France ;  the  second  is,  that  the  principal  markets  for  the 
products  of  English  labor  are  abroad,  while  France 
possesses  thirty-two  millions  ef  consumers  at  home. 

This  last  advantage  in  favor  of  France  is  immense,  be- 
cause nothing  can  deprive  her  of  it,  and  because  it  could 
only  be  compensated  for  by  the  opening  of  numerous  mar- 
kets abroad.  In  England,  agriculture  holds  a  second  place ; 
in  France,  it  takes  the  precedence  over  manufactures. 

The  crises  to  which  agriculture  is  liable,  are  less  fre- 
quent than  those  of  manufactures,  and  are  not  attended 
with  the  same  consequences  ;  periods  of  scarcity  are  never 
so  terrible  in  the  country  as  in  cities  ;  the  farmer  always 
husbands  resources  for  these  calamitous  times,  and  his  sub- 
sistence is  never  made  uncertain. 

The  labors  of  agriculture  maintain  a  frugal,  healthy,  and 
hardy  population ;  those  of  manufactories  often  alter  the 
most  robust  health,  and  dissoluteness  of  all  kinds  is  almost 
always'  an  appendage  of  the  manufacturing  laborer. 

There  is,  then,  no  doubt,  that,  in  many  respects,  agricul- 
tural is  preferable  to  manufacturing  life. 

But,  on  the  other  hand,  the  fortunes  made  in  agriculture 
/  are  slowly  and  laboriously  acquired :  such  a  competition 
in  price  exists  as  to  the  products  of  the  soil,  that  the  profits 
of  the  proprietor  are  necessarily  very  limited  ;  and  although 
agriculture  offers  an  honorable  and  certain  subsistence,  and 
one  presenting  fewer  chances  of  a  reverse,  yet  the  greater 
number  rush  to  manufactures,  as  promising  more  rapid 
gains. 

Governments,  however,  almost  universally  favor  manu- 
factures rather  than  agriculture.  This  predilection  would 
seem  to  be  suggested  to  them  by  the  example  of  England, 
who,  by  means  of  her  manufactures,  has  reached,  in  a  short 
time,  the  highest  degree  of  prosperity. 


224  CHYMISTRY   APPLIED   TO    AGRICULTURE. 

Agriculture  has  yet  this  advantage  over  manufactures, 
that  almost  all  its  products  are  of  the  first  necessity,  and 
that  the  changes  of  taste,  and  the  caprices  of  fashion,  have 
not  the  same  influence  upon  it,  as  upon  the  products  of 
manufacturing  industry :  a  nation  rich  in  its  soil  does  not 
experience  those  fluctuations  to  vv^hich  a  manufacturing 
nation  is  exposed  by  the  mere  progress  of  foreign  manu- 
factures. 

In  all  these  respects,  the  prosperity  of  France  rests 
upon  solid  bases ;  its  soil  is  adapted  to  all  kinds  of  cul- 
ture, and  possesses  several  peculiar  to  itself;  the  excel- 
lence and  variety  of  its  wines,  in  particular,  find  consum- 
ers everywhere,  and  this  branch  of  cultivation  alone  pro- 
duces at  the  present  day  more  than  a  thousand  millions. 

We  are  not,  then,  to  be  surprised  if  France  have  always 
risen,  as  by  a  miracle,  from  every  crisis  which  she  has  ex 
perienced,  and  may  conclude,  that  if  she  had  been  wisely 
governed,  she  would  long  since  have  stood  first  among 
nations. 


CHAPTER  XIIL 

OF    LARGE    AND    SMALL    ESTATES. 

The  question  as  to  large  and  small  estates  has  for  some 
years  occupied  all  minds  in  France.  Some  would  unite 
all  property  in  the  hands  of  a  few  families;  others  are 
willing  to  leave  it  to  time  and  private  interest  to  effect  a 
suitable  division,  and  one  advantageous  to  the  nation  and 
the  government.* 

Large  landed  estates  spring  from  the  first  institutions  of 
monarchy ;  privileges,  grants,  and  the  division  of  inhab- 
itants into  classes,  centre  all  property  in  the  hands  of  a 
few  ;  the  rest  of  the  population,  condemned  to  servitude,  is 
attached  to  the  soil. 

Gradually  the  serfs  are  freed ;  property  is  divided  ;  but 
the  new  proprietors  have  been  able  to  acquire  and  to 
possess  only  on  burdensome  conditions ;   their  lands  have 


*  See  the  excellent  Memoir  of  the  Vicomte  de  Morel  Vind6  on  this 
subject. 


LARGE    AND    SMALL    ESTATES.  225 

been  loaded  with  rents  and  imposts  from  which  the  first 
possessors  were  exempt,  and  thus  two  kinds  of  property  are 
established. 

While  this  state  of  things  has  continued,  agriculture 
has  made  no  progress ;  one  class  was  too  rich  to  perceive 
the  necessity  of  improving  their  estates,  the  other  was  too 
poor  to  attempt  it. 

When  the  power  of  acquiring  property  has  been  given  to 
all,  and  particularly  when  the  law  has  equally  protected 
all  proprietors,  and  abolished  all  privileges  attached  to  the 
soil,  or  to  individuals,  the  result  has  been  a  division  of 
property,  and  an  advance  in  agriculture. 

The  revolution  has  had  two  results  advantageous  to 
land-owners;  the  first,  that  of  effacing  the  last  traces  of 
inequality  in  property;  the  second,  that  of  offering  to  the 
agriculturist  an  enormous  quantity  of  lands,  which  he 
could  purchase  at  a  low  price. 

The  natural  consequence  of  this  state  of  things  has 
been  to  increase  the  number  of  landed  proprietors,  and 
the  respectability  of  the  farmer. 

Is  the  division  of  the  soil  into  small  estates  an  advan- 
tage or  an  evil  ?  That  is  the  question  which  we  are  to 
examine. 

Large  estates  have  the  advantage  of  affording  scope  for 
all  the  developements  of  agricultural  industry.  That 
which  forms  the  basis  of  subsistence,  and  a  large  propor- 
tion of  the  raw  material  of  manufactures,  is  here  united 
in  one  grand  scene  of  operation.  The  productions  of  a 
large  domain  not  only  suffice  for  the  subsistence  and  sup- 
port of  the  proprietor  and  his  agents,  but  the  surplus  sup- 
plies the  wants  of  all,  and  fills  the  public  markets. 

Add  to  this,  that  large  proprietors  are  more  enlightened 
than  small  ones,  and,  especially,  better  enabled,  by  their 
more  ample  fortunes,  to  attempt  improvements. 

There  is,  then,  no  doubt  that  large  proprietors  are  de- 
sirable in  France ;  but  are  we  therefore  to  be  alarmed  at 
the  increase  of  small  farms  ?    I  think  not. 

If,  as  I  have  already  said,  large  estates  have  been  the 
necessary  result  of  our  ancient  institutions,  the  division 
of  landed  property  is  the  natural  effect  of  those  by  which 
we  are  at  present  governed.  The  suppression  of  the  right 
of  primogeniture,  and  of  all  the  burdens  which  weighed 
unequally  upon  different  classes  of  proprietors,  and  the 
prosperity  which   has  prevailed   among  the  inhabitants  of 


226  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

the  country,  have  necessarily  increased  the  number  of 
land-owners ;  but  will  this  increase  be  unlimited  ?  No ; 
it  will  stop  when  the  advantage  of  extensive  agricultural 
operations  is  more  fully  realized,  and  when  the  produce 
of  the  soil  can  no  longer  liberally  pay  the  labor  of  which  it 
is  the  object. 

To  elucidate  this  question,  let  us  see  what  has  taken 
place  hitherto. 

In  districts  devoted  to  the  greater  crops,  the  division  of 
land  has  had  no  sensible  effect;  everywhere  we  find  the 
same  extent  of  agricultural  improvement,  and  the  supplies 
of  cattle,  corn,  fodder,  and  wood  for  the  market  have 
suffered  in  no  way. 

In  a  very  large  number  of  communities,  of  which  al- 
most the  whole  territory  belonged  either  to  the  nobles  or 
to  the  clergy,  those  of  the  inhabitants  who  were  already 
proprietors  have  bought  as  much  as  suited  their  con- 
venience, and  those  who  were  not  proprietors  have  be- 
come so. 

But  it  is  particularly  in  districts  devoted  to  the  lesser 
crops,  that  the  division  of  property  takes  place;  there, 
almost  all  the  labor  is  manual.  The  culture  of  the  vine, 
and  that  of  the  different  kinds  of  pulse,  require  particular 
care  and  intelligent  superintendence.  To  this  the  small 
proprietor  consecrates  all  his  time;  he  labors  at  the  best 
times  and  the  most  favorable  seasons ;  he  employs  the  rest 
of  his  time  in  laboring  for  the  public. 

Let  us  now  observe  the  results  of  the  division  of  the 
soil  into  small  estates. 

These  results  may  be  considered  with  reference  to  three 
points :  the  interest  of  agriculture,  the  welfare  of  the  state, 
and  public  morality. 

1.    The  interest  of  agriculture. 

When  a  large  proprietor  directs  his  information  and 
his  wealth  to  agricultural  improvements,  this  is  without 
doubt  advantageous  to  agriculture ;  but  these  examples 
are  rare.  The  cultivation  of  a  large  domain  is  usually 
entrusted  to  farmers,  who  follow  step  by  step  the  received 
methods,  and  do  not  venture  to  adopt  useful  changes,  be- 
cause the  shortness  of  their  leases  does  not  permit  them 
to  hope  to  reap  the  benefits  of  them.  It  is  rare,  too,  that 
in  a  very  extensive  tillage,  there  is  enough  of  hands,  of 
manure,  and  of  working  cattle,  to  carry  cultivation  to  its 
perfection. 


LARGE    AND    SMALL   ESTATES,  227 

It  cannot  be  denied  that  the  first  interest  of  agriculture 
is  to  produce  the  greatest  possible  amount  upon  a  limited 
extent  of  soil,  and  to  furnish  produce'  at  the  lowest  price 
to  the  consumer :  now,  in  this  case,  all  the  advantage  is 
in  favor  of  the  small  proprietor ;  he  cultivates  the  soil 
himself,  and  brings  to  his  labor  all  the  interest  of  a  pro- 
prietor ;  he  labors  only  at  the  most  favorable  times,  and 
gives  his  unoccupied  time,  for  wages,  to  the  work  of 
others  :  the  large  proprietor  is  not  at  liberty  to  be  thus 
guided  by  his  convenience ;  ho  is  hurried  along  and  com- 
manded by  time  and  labor. 

The  small  proprietor  leaves  no  part  of  his  ground  un- 
occupied ;  he  cultivates  steep  banks  with  pulse ;  plants 
potatoes  in  any  vacant  space  in  his  vineyard  :  the  large 
proprietor  neglects  all  these  details. 

2.    The  loelfare  of  the  state. 

It  is  generally  admitted,  that  the  large  domains,  which 
have  been  divided  in  consequence  of  the  revolution,  pro- 
duce much  more  than  they  did ;  that  uncultivated  lands, 
especially  in  the  south,  are  now  covered  with  noble  vine- 
yards ;  that  prosperity  has  prevailed  in  the  country  from  the 
increase  of  the  number  of  proprietors. 

These  undeniable  facts  have  produced  important  ad- 
vantages ;  the  increase  of  produce  has  furnished  means  for 
the  subsistence  of  a  more  numerous  population.  Wealth, 
introduced  among  the  inhabitants  of  the  country,  has 
enabled  them  to  maintain  their  children,  and  give  them  a 
better  education  ;  the  consumption  of  produce  of  all  kinds 
has  increased,  and  agriculture  and  manufactures  have  found 
larger  markets  for  their  products. 

So  long  as  twelve  years  ago  (I  write  in  1826),  the 
amount  of  taxable  quotas  in  the  land-tax  was  ten  millions 
four  hundred  and  fourteen  thousand  one  hundred  and 
twenty-one,  according  to  the  last  lists  furnished  by  the 
Duke  de  Gaeta.  The  taxable  quotas  under  500  francs 
amounted  to  nine  millions  nine  hundred  and  fifteen 
thousand.  Since  that  time  the  number  of  quotas  has  in- 
creased, and  particularly  the  smaller  ones.  And  never  has 
the  land-tax  been  more  regularly  paid. 

Another  advantage  resulting  to  the  state  fi-om  the  di- 
vision of  property,  has  been  that  of  rendering  changes 
more  frequent,  a  natural  result  of  the  increased  number 
of  proprietors :  these  changes,  as  they  become  more  nu- 
merous, bring  much  more  money  into  the  treasury. 


228  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

According  to  the  very  exact  verification  made  for  five 
years  by  the  department  of  indirect  taxation,  there  were 
produced  on  an  average,  at  the  commencement  of  the  cen- 
tury, thirty-five  millions  and  six  hundred  thousand  hecto- 
litres* of  wine  :  this  amount  has  remarkably  increased  since 
that  time,  not  only  because  the  vine  has  continued  to  be 
planted,  but  because  the  culture  of  it  has  been  improved  : 
the  case  is  almost  the  same  as  to  all  the  produce  of  the 
soil.  It  cannot  be  denied  that  this  increase  of  production  is 
the  result  of  the  division  of  the  soil  into  small  farms.  I 
have  been  for  some  time  the  proprietor  of  a  pretty  extensive 
vineyard,  which  I  carefully  cultivate,  and  I  have  constantly 
observed,  that  the  small  proprietors  who  worked  for  me 
raised  at  least  double  from  an  equal  extent  of  land  belong- 
ing to  them  ;  my  produce,  in  truth,  was  of  a  little  superior 
quality ;  but,  at  the  market  price,  the  quantity  more  than 
compensated  for  this  difference  in  quality. 

3.  Public  morality. 

But  it  is  particularly  as  it  respects  public  morals  that  the 
increase  of  the  number  of  small  proprietory  is  advantageous. 
To  be  convinced  of  this,  we  need  only  compare  the  condi- 
tion of  the  man  possessing  no  property,  with  that  of  the  pos- 
sessor of  property,  however  limited  in  extent. 

The  laborer  without  property  is  retained  only  by  habit 
in  the  place  of  his  birth ;  his  two  hands  are  his  only  prop- 
erty, and  he  places  them  at  the  disposal  of  him  who  pays 
best ;  he  is  entirely  dependent  upon  the  work  he  finds 
about  him,  and  when  employment  fails,  he  changes  with- 
out regret  his  place  of  abode,  to  seek  it  elsewhere.  The 
institutions  of  his  country  are  indifferent  to  him,  because 
he  takes  no  part  in  public  aff'airs ;  he  feels  no  interest  in 
the  preservation  of  order,  because  a  state  of  disorder  pre- 
sents to  him  more  favorable  opportunities.  Almost  always 
discontented  with  his  situation,  he  becomes  restless,  jeal- 
ous, miserable ;  he  accuses  God  and  man,  and  seeks  every 
opportunity  which  offers  of  rendering  it  better.  Troubles, 
insurrections,  robberies,  assassinations  are  frequent  wher- 
ever there  are  many  laborers  without  property  and  few 
proprietors ;  and  governments  are  forced  to  establish 
enormous  poor-rates,  as  in  England,  or  to  supply  the  poor 
with  food  at  the  gates  of  convents  or  chateaux,  as  in 
Spain. 

*  See  note,  page  131. 


LARGE    AND    SMALL   ESTATES.  ^^ 

The  subsistence  of  the  laborer  without  property  is  never 
certain ;  the  frequent  diminution  or  suspension  of  labor  in 
manufacturing  establishments  reduces  him  to  misery,  and 
promotes  the  developement  of  all  the  vices  which  result 
from  it;  the  labors  of  the  country  vary  with  times  and 
seasons,  and  do  not  offer  constant  employment  to  one  not 
attached  to  the  farm.  His  lot  is  then  always  variable  and 
precarious. 

The  man  without  property  who  is  single,  commonly  leads 
a  dissolute  and  intemperate  life :  he  who  would  have  a  family 
commonly  becomes  more  unhappy ;  he  cannot  give  his  chil- 
dren a  suitable  education,  and  they  soon  contract  all  the  vices 
of  a  depraved  society. 

The  condition  of  the  small  proprietor  is  very  different 
from  this ;  he  is  rooted  to  the  soil,  and  thence  derives  all  the 
advantages  of  his  situation.  He  works  on  his  own  land  in 
his  leisure  moments,  and  devotes  the  rest  of  his  time  to 
earning  wages  on  the  estates  of  others.  This  double  source 
of  profit  abundantly  secures  his  existence  and  that  of  his 
family.  His  children  and  his  wife  cooperate  in  the  culture 
of  his  little  farm  ;  idleness  is  banished  from  their  household, 
and  good  morals,  which  are  always  the  result  of  a  laborious 
life,  prevail  there. 

The  small  proprietor  is  interested  in  the  maintenance  of 
public  order,  because  he  would  be  a  loser  by  trouble  and 
disorder  ;  he  loves  the  institutions  and  the  government  which 
protect  his  property ;  he  regards  the  welfare  of  others,  be- 
cause he  would  have  others  regard  his  own.  His  interest, 
his  affections,  his  fears,  his  hopes,  are  concentrated  and 
repose  in  that  little  spot  of  earth  whose  safety  and 
prosperity  are  his  only  wish.  He  has  in  truth  a  country, 
whilst  the  other  is  a  true  cosmopolite,  a  stranger  to  all  social 
interest. 

Some  appear  to  be  alarmed  at  the  increase  of  population 
attendant  upon  small  proprietorship;  but  this  increase  of 
population  is  a  certain  sign  of  an  increase  of  the  means  of 
subsistence  and  of  the  wealth  of  the  inhabitants,  whilst  the 
diminution  of  population  announces  public  misery. 

In  proportion  as  the  population  of  the  country  increases, 
manual  labor  becomes  more  abundant,  and  produce  increases 
in  quantity  and  is  reduced  in  price. 

Thus,  stripping  the  question  of  all  that  is  connected 
with  certain  political  considerations,  the  division  of  land* 
20 


230  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

ed  property  is  an  advantage  to  agriculture,  to  the  state,  tO' 
public  morals. 

Men  who  take  their  opinion  only  from  the  past,  would 
bring  back  property  to  its  former  state ;  but  times  are  not 
the  same,  and  a  return  to  the  ancient  order  of  things  is 
impossible.  The  division  of  property  will  continue  to  take 
place,  so  long  as  the  small  proprietor  shall  obtain  more 
produce  from  a  given  extent  of  land  than  the  large  one, 
and  so  long  as  large  owners  shall  divide  their  lands  into 
small  lots,  to  obtain  a  more  advantageous  sale  of  them.; 
it  is  evident  that  a  different  result  could  be  obtained  only 
by  reducing  the  destitute  laborer  to  a  degree  of  misery 
which  would  not  permit  him  to  economize  with  a  view  to 
acquiring  property,  or  by  prohibiting  sales  of  land  in  small 
portions ;  now,  the  first  of  these  means  is  contrary  to  jus- 
tice and  good  morals,  and  the  second  to  the  rights  of  prop- 
erty. 

When,  in  the  session  of  1825,  the  government  proposed 
to  reestablish  the  right  of  primogeniture,  it  had  neither 
paid  regard  to  the  changes  which  had  taken  place  since 
the  revolution,,  nor  to  the  respective  rights  of  the  different 
members  of  the  same  family.  Formerly,  almost  all  the 
large  estates  belonged  to  the  most  ancient  families  in  the 
kingdom ;  they  passed,  undivided,  into  the  hands  of  the 
eldest  son,  because  the  army,  the  clergy,  or  the  order  of 
Malta  afforded  rich  endowments  for  younger  sons,  and  con- 
vents offered  great  resources  for  daughters ;  but,  at  the 
present  day,  what  would  become  of  younger  sons  if  the 
right  of  primogeniture  were  reestablished?  Deprived  of 
the  expedients  offered  by  the  old  state  of  things,  incapable 
of  laboring  upon  the  soil,  they  would  live  at  the  mercy  of 
the  head  of  their  family.  It  is  then  particularly  to  old 
families,  which,  notwithstanding,  it  is  meant  to  benefit, 
that  the  reestablishment  of  the  right  of  primogeniture 
would  be  fatal. 

Let  us  but  leave  it  to  time  and  to  private  interest,  and  the 
division  of  property  will  not  pass  the  bounds  prescribed  to  it 
by  these  supreme  regulators  of  all  things. 

The  division  of  estates  will  continue  to  take  place,  1.  in 
the  vicinity  of  cities,  where,  from  the  constant  attention 
bestowed  on  the  soil,  from  the  abundance  of  manure,  the 
facility  of  transportation,  the  proximity  of  the  market,  and 
the  certainty  of  a  safe  and  advantageous  sale,  immense 
crops  of  vegetables  and    fruits  of   all  kinds  and  of  every 


LARGE    AND    SMALL    ESTATES.  231 

season  may  be  obtained  by  manual  labor;  2.  in  vine  coun- 
tries, where  the  cultivation  requires  constant  labor,  and 
where  the  production  is  always  proportional  to  the  care 
bestowed  upon  the  land ;  3.  in  uneven  lands,  like  valleys, 
mountains,  &lc.  where  cultivation  is  confined  within  narrow 
limits,  and  where  the  lands  capable  of  it  are  separated  by  a 
barren  soil. 

In  all  these  cases,  the  plough  and  working-cattle  can- 
not be  employed  in  labor ;  every  thing  is  done  by  manual 
labor,  and  at  most,  the  owner  of  each  estate  possesses  a 
few  cows  and  goats,  and  sometimes  a  few  sheep,  to  secure 
subsistence,  and  increase  the  comfort  of  his  household. 
We  often  find  a  numerous  population  assembled  in  those 
wild  places  where  the  soil  seems  to  refuse  any  cultiva- 
tion, and  where  the  inhabitant,  temperate  and  hardy,  ob- 
tains, by  industrious  labor,  crops  which  satisfy  his  wants 
and  supply  the  neighboring  markets.  Those  numerous 
countries,  which  are  not  capable  of  high  cultivation,  would 
be  deserted  without  the  assistance  of  the  small  proprietor ; 
and  it  may  be  said,  to  his  credit,  that  he  creates  produce 
in  places  which  nature  had  devoted  to  the  most  complete 
sterility. 

We  nowhere  see  small  proprietorships  existing  in  places 
favorable  to  high  cultivation.  The  vast  domains  of  Beauce, 
Brie,  Soissonnais,  Upper  Languedoc,  exist  undivided,  and 
are  always  the  granaries  oT  France ;  the  rich  pasture  lands 
of  Normandy,  Poiton,  Anjou,  &c.  always  maintain  the 
same  number  of  cattle  ;  our  large  forests  have  remained 
untouched ;  population  and  the  means  of  living  have  con- 
siderably increased ;  our  markets  are  abundantly  supplied ; 
wealth  lias  spread  through  the  country ;  saanufactures  have 
made  immense  progress ;  taxes  are  paid  regularly  and  with- 
out compulsion. 

Let  us  beware  of  disturbing,  by  laws  or  regulations 
relative  to  property,  this  general  harmony  and  public  pros- 
perity, which  secure  the  happiness  and  prosperity  of  our 
countrj. 


232  CHYMISTRY    APPLIED    TO    AGRICULTURE. 


CHAPTER    XIV. 

THE    ENCOURAGEMENT   WHICH    OUGHT    TO    BE    GIVEN   BY    THE 
GOVERNMENT    TO    FRENCH    AGRICULTURE. 

The  very  limited  degree  of  information  which,  even  to 
the  present  day,  has  been  diffused  in  the  country,  and  the 
almost  abject  part  which  the  cultivator  of  the  soil  has  been 
made  to  play,  have  arrested  the  progress  of  agriculture 
there  ;  faulty  methods  of  cultivation  have  been  retained,  and 
France  has  been  far  outstripped  by  other  nations  in  this  no- 
ble career  of  public  prosperity. 

Now  that  our  institutions  have  replaced  the  most  useful 
class  of  men  in  the  first  rank  in  society,  it  is  to  be  hoped 
that  the  agriculturist  will  feel  all  his  dignity,  that  he  will 
love  his  condition,  and  that,  by  labor  and  instruction,  he  will 
create  resources  hitherto  unknown  to  him.  But  this  useful 
revolution  requires  the  support  of  government ;  lands  are  too 
much  divided,  the  fortunes  of  proprietors  are  too  limited,  to 
allow  the  expectation  of  seeing  great  examples  and  useful 
lessons  given  without  public  assistance. 

In  France,  the  most  frivolous  arts  are  almost  everywhere 
provided,  at  the  cost  of  government,  with  the  facilities  for 
practical  instruction ;  and  agriculture  alone  is  destitute  of 
a  public  establishment,  where  the  principles,  and  practice 
of  this  beautiful  science  may  be  taught.  The  need  of 
communicating  instruction  through  the  country  is  so  gen- 
erally felt,  that  we  see,  in  every  department,  educated  ag- 
riculturists associated  for  the  purpose  of  communicating 
their  observations,  of  discussing  new  processes,  and  of 
proposing  the  improvements  of  which  agriculture  is  sus- 
ceptible. 

These  associations  are  useful ;  they  render  important 
services;  but  they  have  not  the  advantage  of  forming 
young  agriculturists,  nor  of  making  them  acquainted  with 
the  true  principles  of  the  science.  We  need,  for  this  ob- 
ject, special  instruction  and  men  who  shall  be  exclusively 
devoted  to  it. 

In  England,  where  rural  fortunes  are  divided  among 
from  twenty-two  to  twenty-five  thousand  families,  wealthy 
proprietors  establish  prizes,  of  which  they  make  a  formal 
distribution  every  year.  They  assemble  within  their  do- 
mains, upon  a  fixed  day,  a  considerable  number  of  agricul- 


DUTIES    OP    THE    GOVERNMENT.  233 

turists,  each  one  of  whom  produces  for  examination  and  de- 
cision the  finest  products  of  his  cultivation.  These  festivals, 
instituted  for  the  promotion  of  agriculture,  excite  the  most 
active  emulation  and  produce  the  happiest  effects. 

It  has  been  in  vain  attempted,  in  France,  to  imitate  Eng- 
land; fortunes  are  here  too  limited  to  enable  individuals  to 
meet  expenses  so  considerable.  Government  alone  can  and 
ought  to  furnish  such  institutions. 

It  would  be  necessary  that  at  least  two  experimental 
schools  of  agricultural  instruction  should  be  established  in 
France,  one  in  the  south,  and  the  other  in  the  north,  in  order 
to  embrace  all  kinds  and  varieties  of  culture  which  belong 
to  our  soil  and  our  climate. 

The  extent  of  land  devoted  to  each  establishment  should 
be  about  two  hundred  hectares*  and  the  buildings  should  be 
able  to  lodge  at  least  one  hundred  pupils. 

The  nature  of  the  soil  must  be  sufficiently  varied  to  ad- 
mit of  all  the  different  kinds  of  culture  adapted  to  the 
climate. 

There  would  be  required  in  each  establishment  a  director, 
entrusted  with  the  care  and  management  of  it,  and  two  pro- 
fessors, one  of  Chymistry  applied  to  Agriculture,  the  other 
of  Veterinary  Medicine. 

The  purchase  of  lands  and  the  cost  of  the  establishment 
might  be  estimated  at  from  a  million  to  twelve  hundred 
thousand  francs;  but  the  money  paid  for  board  and  the 
profits  of  cultivation  would  at  least  cover  ail  the  annual 
expenses. 

It  would  be  useful  to  connect  with  each  establishment  a 
workshop,  for  the  manufacture  of  all  implements  of  husband- 
ry, perfected  or  newly  invented,  or  employed  in  rural  opera- 
tions. The  profits  of  the  workshop  would  form  a  consider- 
able revenue  for  the  establishment. 

The  young  people  admitted  into  the  establishment  as 
boarders  should  be  employed  in  all  agricultural  labors ;  they 
should  be  instructed  in  the  responsible  management  of  an 
estate. 

There  should  annually  be  a  formal  distribution  of  prizes 
to  those  pupils  who  have  distinguished  themselves  by 
good  conduct,  and  to  those  who  have  made  the  greatest 
progress. 

A  royal  ordinance  should  establish  these  principles,  and 

*  The  hectare  is  equal  to  2  acres,  1  rood,  35.4  perches. 
20* 


234  CHYMISTRY    APPLIED    TO    AGRICULTURE, 

the  Minister  of  the  Interior  should  make  the  rules  necessary 
for  securing  their  execution  in  every  particular. 

I  have  no  doubt  that  these  two  establishments  would 
produce,  in  a  few  years,  the  best  effects  upon  French  ag- 
riculture. The  pupils  who  left  these  schools  would  diiffuse 
everywhere  instruction  and  good  methods  of  cultivation, 
and  the  first  of  arts  would  no  longer  depend  for  preserva- 
tion on  a  mere  routine,  which  perpetuates  errors  and  pre- 
judices. 

In  establishing  these  two  schools,  the  government  will 
have  fulfilled  only  one  part  of  its  duties  to  agriculture ;  it 
owes  it  roads  and  canals  to  facilitate  the  transportation  of 
commodities ;  it  owes  it  a  wise  regulation  of  taxes,  so  that 
they  may  never  represent  a  single  part  only  of  the  benefit 
derived  from  agricultural  operations ;  it  owes  it  a  kind  and 
paternal  administration;  it  owes  it  assistance  when  acci^ 
dent  at  casualties  ox  diseases  \idiWQ  ravaged  crops  and  destroyed 
cattle. 

And  even  in  this,  the  government  has  not  yet  fulfilled 
all  its  duties  to  agriculture,  to  their  full  extent ;  it  should 
excite  emulation,  w^hich,  in  the  arts,  works  miracles,  and 
should  reward  agriculturists  who  make  important  discove- 
ries, and  those  who  improve  or  extend  useful  methods  of 
cultivation. 

These  pecuniary  encouragements  should  not  be  distributed 
at  random,  nor  badly  bestowed,  for  they  would  then  extin- 
guish emulation  in  place  of  rousing  it. 

A  well-selected  jury  should  designate,  every  year,  to  the 
authorities,  those  cultivators  of  the  department  who  have  de- 
served best  of  agriculture ;  and  the  distribution  of  prizes 
should  be  made  in  a  public  and  solemn  sitting. 

The  object  of  the  examinations  of  the  jury  should  be  to 
determine  who  are  those  agriculturists  who  have  introduced 
upon  their  estates  animals  more  valuable  and  more  useful 
than  those  of  the  country,  and  those  who  have  improved  the 
native  breeds ; 

Those  who  have  established  the  system  of  cropping  most 
favorable  to  the  soil  ; 

Those  who  have  discovered  modes  of  manuring  and  im- 
proving the  soil,  before  unknown  .or  not  used ; 

Those  who  have  planted  the  largest  number  of  trees ; 

Those  who  have  opened  to  culture  lands  hitherto  barren  ; 

Those  who  have  introduced  the  cultivation  of  plants,  the 
produce  of  which  is  more  profitable  than  that  of  those  usual- 
ly raised ; 


DUTIES    OF   THE    GOVERNMENT.  235 

Those  who  have  invented  or  unproved  agricultural '  imple- 
ments ; 

In  a  word,  all  those  who  should  have  rendered  services  in 
any  department  of  agriculture,  would  be  entitled  to  these 
rewards. 

I  believe  that  prizes  to  the  amount  of  ten  or  twelve  thou- 
sand francs,  annually  distributed  in  each  of  the  principal  de- 
partments, would  be  sufficient  to  excite  a  happy  emulation 
among  agriculturists. 

The  government  should  also  reserve  to  itself  some  places 
in  the  two  practical  schools  of  agriculture,  and  there  place 
the  children  of  the  most  distinguished  cultivators,  to  be 
maintained  at  its  expense. 

But  it  is  not  enough  to  create  agricultural  products ;  chan- 
nels must  be  opened  to  them,  and  a  market  secured;  and 
thus  the  government  has  other  duties  to  fulfil.  Whatever 
facilitates  transportation  will  become  of  general  utility,  by 
increasing  the  consumption  of  commodities,  and  lowering 
their  price  ;  the  first  object  of  attention  is  then  the  means  of 
attaining  this  end. 

To  arrive  at  a  conclusion  respecting  these  means,  we  must 
first  state  the  present  condition  of  things. 

There  are  some  roads,  which  may  be  called  parish  roads, 
which  merely  form  a  communication  between  the  estates  of 
one  parish ;  these  consequently  are  merely  roads  for  farming 
operations. 

There  are  others,  which  form  a  communication  between 
adjacent  parishes,  and  which  may  be  called  district  roads. 

There  are  also  others,  which  connect  together  all  the 
towns  of  a  department,  which  may  be  called  departmental 
roads. 

And  finally,  the  great  roads,  which  form  communications 
between  all  the  departments. 

The  care  of  maintaining  parish  or  farm  roads  is  entrusted 
to  the  local  authorities,  and  one  needs  only  a  hasty  journey 
through  France,  to  be  convinced  of  the  neglect  and  care- 
lessness with  which  these  communications  are  treated. 
Transportation  on  these  roads  is  difficult  and  tedious ;  twice 
the  number  of  animals  are  employed  upon  them  which 
would  be  necessary  if  the  roads  were  kept  in  a  proper  state, 
and  the  price  of  commodities  is  increased  by  the  difficulty 
of  transportation ;  all  this  is  detrimental  to  the  proprietor, 
who  indeed  admits  it,  but  no  one  is  willing,  at  his  own  ex- 
pense, to  make  repairs  by  which  all  would  be  benefited,  and 
the  evil  continues. 


236  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

To  obviate  these  inconveniences,  it  virould  be  necessary 
that  each  municipal  council  should  prepare  a  statement  of 
all  the  neighboring  roads,  and  of  all  the  improvements  which 
they  require ;  this  statement  should  be  submitted  to  the  sub- 
prefect,  vi^ho  should  send  it  to  the  mayor,  with  his  opinion 
thereon ;  the  expense  should  be  assessed  upon  the  proprie- 
tors at  so  much  per  franc  of  their  land-tax  in  the  parish. 

If  it  is  difficult  to  induce  the  proprietors  of  a  single  par- 
ish to  contribute  to  the  maintenance  of  their  farming  roads, 
it  is  much  more  so  to  bring  two  parishes  to  unite  in  the 
repairs  of  their  district  roads.  The  rivalry  often  existing 
between  them,  the  greater  or  less  interest  which  they  have 
in  the  use  of  the  rx)ad,  are  obstacles  in  the  way  of  the  com- 
mon good. 

It  is  here  that  the  authorities  should  interpose.  Already, 
almost  everywhere,  the  district  roads  have  been  usurped  by 
the  neighboring  proprietors,  and  it  is  not  by  means  of  the 
local  authorities  that  a  redress  of  these  grievances  can  be 
hoped  for ;  for  the  members  of  the  municipal  councils  and 
of  the  municipalities,  themselves  the  largest  proprietors  in 
the  parishes,  are  the  first  usurpers. 

I  would  have  attached  to  every  department  a  superintend- 
ent of  bridges  and  highways,  whose  duties  should  be  confin- 
ed to  whatever  relates  to  the  district  roads.  A  stranger  to 
all  local  interests,  he  should  prepare  a  plan  of  the  district 
roads,  should  reduce  within  the  limits  of  their  own  estates 
those  who  have  encroached  upon  the  public  road,  should 
prescribe  the  necessary  repairs,  point  out  the  nature  of  the 
materials  to  be  employed,  and  direct  all  the  labor ;  and  all 
his  plans  should  be  put  in  execution,  afi;er  having  been  sub- 
mitted to  the  engineers  of  the  arrondissement,  and  approved 
by  the  chief  engineer. 

.  The  parishes  interested  should  pay  the  expenses  by  an 
assessment  upon  their  revenue,  their  additional  centimes, 
and  partly  by  a  payment  in  kind,  with  the  approbation  of 
the  prefect. 

The  departmental  roads,  which  form  communications  be- 
tween the  principal  town^of  a  department,  are  of  more  gen- 
eral use  and  interest  than  those  of  which  we  have  just  been 
speaking ;  these  should  be  maintained  at  the  expense  of  the 
department  itself;  and  the  general  council,  to  which  funds 
are  entrusted  for  this  object,  should  make  it  one  of  its  prin- 
cipal subjects  of  deliberation. 

The  great    roads,  which   traverse    all    the  departments, 


DUTIES    OF    THE    GOVERNMENT.  237 

are  of  general  interest,  and  should  be  established,  superin- 
tended, and  maintained  by  the  government  itself. 

These  four  kinds  of  communication  correspond  to  each 
other,  and  are  bound  together  by  a  common  interest ;  they 
may  be  regarded  as  arteries  in  the  social  body,  which  carry 
life  to  every  part. 

When  these  channels  of  communication  shall  be  well  di- 
rected and  carefully  maintained,  transportation  will  become 
more  easy,  more  prompt,  and  cheaper,  all  which  is  for  the 
advantage  of  agriculture ;  we  shall  no  longer  see  portions  of 
the  population  enclosed  within  very  narrow  limits,  and  con- 
demned to  produce  no  more  than  they  can  consume,  and  to 
derive  but  small  advantage  from  certain  natural  products, 
such  as  the  wood  which  crowns  the  summits  and  covers  the 
sides  of  almost  all  our  mountains. 

These  communications,  established  through  the  country, 
will  not  only  tend  to  facilitate  the  interchange  of  commod- 
ities and  to  increase  production,  but  will  have  a  favorable 
influence  upon  civilization.  By  bringing  the  inhabitants 
nearer  to  each  other,  they  establish  improving  social  rela- 
tions between  them ;  mutual  assistance  is  rendered ;  mu- 
tual instruction  afforded  in  the  art  of  cultivation ;  and 
society,  in  its  turn,  profits  by  all  these  facilities  for  social 
union. 

If  to  these  communications  by  land,  rendered  as  easy  and 
as  extensive  as  necessity  requires,  we  add  the  immense  ad- 
vantages of  navigation  upon  rivers  and  canals,  agriculture 
will  soon  have  little  to  ask  of  government. 

There  are  few  parts  of  France  where  canals  cannot  be 
made,  or  the  navigation  of  rivers  improved.  When  the 
grand  scheme  of  navigation,  which  has  been  for  three  years 
provided  for  by  a  law,  shall  be  executed,  great  means  of  com- 
munication will  be  opened  ;  and  it  only  remains  to  terminate 
this  excellent  system  by  branches,  to  secure  to  France  all 
the  benefit  of  navigation. 

Then  the  varied  productions  of  France  will  be  conveyed 
to  all  points ;  the  price  of  commodities  will  everywhere 
diminish,  consumption  will  necessarily  increase,  and  we  shall 
not  again  see  one  district  exposed  to  the  scourge  of  famine, 
without  others  being  able  to  supply  it,  except  at  a  great 
expense. 


238  CHYMISTRY   APPLIED   TO   AGRICULTURE. 

CHAPTER    XV. 

ON    FERMENTATION. 

The  process  of  decomposition  commences  in  all  the  pro- 
ducts of  vegetation,  as  soon  as  they  are  ripe,  or  separated 
from  the  plant.  Air,  heat,  and  water,  which  before  this 
concurred  in  promoting  their  formation  and  growth,  be- 
come now  the  principal  agents  in  the  changes  which  they 
undergo. 

The  appearances  and  the  new  products  resulting  from  the 
decomposition  of  bodies,  vary  according  to  the  nature  of 
their  constituent  principles. 

Generally  speaking,  all  vegetable  substances  decay  when 
left  to  experience  spontaneous  decomposition  ;  but  when,  by 
being  exposed  to  mechanical  pressure,  those  parts  of  the 
fruits  which  have  been  separated  are  again  mixed,  there 
arises  a  new  product.  The  grape,  for  instance,  rots  upon 
the  vine,  whilst  the  juice  expressed  from  it  undergoes 
the  vinous  fermentation.  It  has  for  a  long  time  been  in 
the  power  of  art  to  excite,  retard,  and  modify  decomposition, 
so  as  to  form  new  articles  of  food  and  drink,  for  men  and 
animals. 

In  vegetable  products,  all  the  principles  are  in  a  state  of 
combination  and  saturation,  one  with  the  other :  whilst 
the  plant  lives,  its  organic  energies  exert  an  influence 
over  external  agents,  and  preserve  in  their  natural  propor- 
tions the  elements,  which  enter  into  the  composition  of  the 
products. 

As  soon  as  a  plant  dies,  or  a  fruit  becomes  ripe,  a  new 
order  of  things  taj^es  place ;  the  different  parts  of  the  vege- 
table, being  no  longer  influenced  by  the  laws  of  vitality, 
become  subject  to  the  power  of  external  agents ;  air,  wa- 
ter, and  heat  exercise  over  them  an  almost  absolute  sway ; 
oxygen,  by  depriving  them  of  their  carbon,  destroys  the 
proportions  of  their  constituent  principles;  water  produces 
the  same  effect  by  dissolving  certain  portions  of  the  sub- 
stance ;  and  heat,  by  separating  the  particles,  weakens 
their  union,  and  facilitates  the  action  of  the  two  other 
powers. 

According  to  the  experiments  of  M.  Gay-Lussac,  the 
juice  of  grapes  expressed  in  a  vacuum  does  not  ferment ; 
but  from  the  moment  that  the  air  is  allowed  admittance  to 


FERMENTATION.  239 

it,  fermentation  takes  place,  and,  without  farther  assistance 
from  air,  goes  through  all  its  stages. 

Nearly  all  the  methods  made  use  of  at  the  present  time 
for  preserving  animal  and  vegetable  substances  from  decom- 
position, are  founded  upon  preserving  them  from  the  action 
of  air,  water,  and  heat,  as  I  have  already  shown. 

At  the  moment  when  the  air,  or  any  other  external  agent, 
deprives  a  vegetable  of  ever  so  small  a  portion  of  one  of  the 
elements  which  enter  into  its  composition,  the  body  be- 
comes imperfect,  the  proportions  between  the  principles  are 
no  longer  what  they  should  be,  and  decomposition  cainnot  be 
prevented ;  there  vvill  then  be  formed  new  products  by  the 
union  of  the  elements  of  the  vegetable  among  themselves, 
or  by  their  combination  with  the  foreign  bodies  which  act 
upon  them. 

When  a  dead  body  is  disorganized  by  mingling  together 
all  its  principles,  decomposition  proceeds  either  with  greater 
or  less  rapidity,  because  the  affinity  between  the  parts  being 
awakened,  the  several  agents  act  more  readily  upon  it. 

Whenever  man  wishes  to  appropriate  to  his  own  use  the 
product  of  a  fermentation,  it  is  necessary  for  him  to  inter- 
fere by  directing  the  progress  of  it.  The  greatest  number 
of  fruits  contain  all  the  elements  necessary  for  forming  the 
vinous  fermentation ;  but  these  elements  are  separate  in 
them,  and  it  is  therefore  necessary  to  mix  and  incorpo- 
rate them  together  by  the  expression  of  the  fruit,  to  produce 
this  fermentation.  The  leaves  and  the  woody  fibre  of  plants 
are  susceptible  of  putrid  decomposition  ;  but  in  order  to  pro- 
duce it,  they  must  be  heaped  together  and  moistened  with 
water. 

To  produce  a  speedy  fermentation  of  juices,  it  is  neces- 
sary to  collect  them  in  a  convenient  quantity,  and  expose 
them  to  a  determined  degree  of  heat :  without  these  pre- 
cautions there  will  be,  to  be  sure,  decomposition,  but  often 
without  any  useful  result. 

The  vinous  fermentation  is  the  most  important  of  any,  by 
reason  of  the  usefulness  of  its  products;  I  shall,  therefore, 
speak  particularly  upon  it. 

The  vinous  fermentation  takes  place  only  when  two  prin- 
ciples of  very  different  natures  act  upon  and  decompose 
each  other :  the  result  of  this  decomposition  is  alcohol. 
The  first  of  these  principles  is  sugar  ;  the  second  is  a  sub- 
stance very  similar  to  animal  gluten,  which  is  found  more  or 
less  abundantly  in  the  various  kinds  of  grain,  and  in  the 
juice  of  some  fruits. 


^40  CHYMISTRY   APPLIED   TO    AGRICULTURE. 

• 

Those  fruits  from  which  the  juice  is  expressed  to  undergo 
the  vinous  fermentation,  contain  both  these  principles,  but 
they  exist  in  them  separately :  the  extraction  of  the  juice  by 
pressure,  mixes  them  intimately,  and  they  then  act  upon  and 
decompose  each  other. 

In  well-ripened  grapes,  the  two  principles  exist  in  the 
exact  proportions  for  producing  the  best  results  from  fer- 
mentation ;  bat  in  the  grains  which  are  equally  used  for  the 
fabrication  of  spirituous  liquors,  the  sugar  is  separated  when 
the  grain  is  made  to  germinate,  before  being  submitted  to 
fermentation.* 

Some  of  the  substances  which  by  fermentation  yield  al- 
cohol, require  the  addition  of  some  foreign  matter,  in  order 
that  fermentation  may  commence  and  pass  regularly  through 
its  various  stages.  The  substance  used  for  exciting  fer- 
mentation, is  called  leaven,  ferment,  or  yeast;  and  is  al- 
most always  a  partially  fermented  matter  containing  a  large 
portion  of  the  vegeto-animal  principle.  The  scum  which 
rises  upon  the  top  of  liquids  undergoing  fermentation,  or  a 
fermented  dough  of  wheat,  rye,  or  barley,  is  used  for  this 
purpose. 

Leaven,  when  mixed  with  any  liquid  containing  sugar, 
continues  to  ferment,  and  communicates  the  action  through 
the  whole  extent  of  it. 

When  the  must  of  grapes  has,  by  boiling  and  evapora- 
tion, been  reduced  to  the  state  of  an  extract,  the  vegeto- 
animal  principle  contained  in  it  is  disorganized,  and  it  can- 
not be  made  to  ferment  without  the  addition  of  some  foreign 
body. 

In  order  that  fermentation  may  pass  regularly  through 
its  several  stages,  and  furnish  a  product  free  from  all  ten- 
dency to  a  spontaneous  and  final  decomposition,  it  is  ne- 
cessary that  the  sugar  and  leaven  should  exist  in  the  sub- 
stance in  suitable  proportions  : — if  the  proportion  of  sugar 
be  too  great,  it  will  not  be  entirely  decomposed,  and  the 
fermented  liquor  will  retain  a  sweet  taste :  if,  on  the  other 
hand,  the  quantity  of  leaven  predominate,  a  part  of  it  will 
remain  undecomposed  in    the  mass,  and   the    nature  of  it 

*  In  the  process  of  germination,  oxygen,  which  is  the  sole  agent, 
combines  with  the  carbon,  and  causes  the  developement  of  sugar  in 
the  grain.  However,  the  fermentation  of  grain  which  has  not  first 
germinated,  produces  gradually  the  same  results  when  distilled ;  as 
the  first  effect  of  fermentation  as  well  as  of  germination  is  to  throw 
off  carbon. 


FERMENTATION.  241 

being  changed  by  fermentation,  it  wilJ  become  in  time  sour 
or  putrid,  according  to  the  nature  of  the  body  upon  which 
it  acts. 

Generally  speaking,  the  French  grapes  when  ripe  contain 
such  proportions  of  sugar  and  the  vegeto-animal  principle 
as  are  well  adapted  for  producing  the  vinous  fermentation ; 
but  when  the  summer  is  cold  or  damp,  the  proportion  of 
sugar  is  less,  and  the  predominance  of  the  mucilage  renders 
the  liquor  weak.  In  this  case,  the  small  quantity  of  alcohol 
which  is  developed  is  not  sufficient  to  preserve  the  wine 
from  spontaneous  decomposition,  and  at  the  return  of  heat, 
a  new  fermentation  takes  place,  the  product  of  which  is 
vinegar.  This  evil  may  be  easily  obviated  by  artificial 
means :  it  is  only  necessary  to  add  to  the  liquor  such  a  quan- 
tity of  sugar  as  would  naturally  have  been  found  in  it,  under 
usual  circumstances. 

For  ascertaining  the  quantity  of  sugar  which  belongs  to 
the  must  of  well-ripened  grapes,  the  following  hints  will  be 
sufficient. 

In  the  south  of  France,  the  grapes  usually  arrive  at  a  state 
of  perfect  maturity,  and  if  the  fermentation  be  well  conduct- 
ed, the  wine  will  keep  well ;  but  in  the  north,  however  fa- 
vorable the  season  may  be,  the  grapes  never  become  perfect- 
ly ripe.  I  have  always  observed  that  the  wine  of  the  south, 
which  had  been  well  fermented,  marked  upon  the  aerometer 
some  fractions  of  a  degree  below  the  specific  gravity  of  wa- 
ter, whilst  the  new  wines  of  the  north  rarely  cause  the 
aerometer  to  descend  to  the  same  degree. 

Another  important  circumstance  by  which  we  must  be 
guided  in  ascertaining  the  quantity  of  sugar  necessary  to  be 
employed,  is  the  degree  of  concentration  of  the  must :  this 
varies  with  every  vintage,  and  the  aerometer  has  often  indi- 
cated to  me  a  difference  of  concentration,  varying  from  2" 
to  4°  (zz:  specific  gravity  of  1.014  to  1.029,)  in  the  must 
procured  from  the  same  vineyard,  according  to  the  state  of 
ripeness  which  the  fruit  had  acquired  ;  the  heaviest  must  be- 
ing furnished  by  the  ripest  grapes. 

In  Touraine,  and  upon  the  borders  of  the  Cher  and  the 
Loire,  the  weight  of  the  must  varies  from  8.5°  to  11°; 
(=.  specific  gravity  of  1.063  to  1.083.)  I  have  observed  it 
in  the  south  to  range  between  10°  and  16°  (=z  specific 
gravity  of  1.075  to  1.125.)  Having  once  ascertained  the 
specific  gravity  of  the  must  obtained  fi-om  perfectly  ripe 
grapes,  it  is  only  necessary  to  bring  to  the  same  weight,  by 
21 


242  CHYMiSTRY    APPLIED    TO    AGRICULTURE. 

the  addition  of  a  sufficient  quantity  of  sugar,  the  must  of 
such  grapes  as  grow  in  seasons  less  favorable  to  their  ma- 
turity. 

In  1817  the  grapes  of  Touraine  did  not  ripen  well,  and 
consequently  the  must  from  my  vintage,  which  in  favorable 
years  marks  11°  {z=  specific  gravity  of  1.083,)  stood  only  at 
9°  (=  sp.  gr.  1.067.)  I  raised  it  to  11°  (=  sp.  gr.  1.083,) 
by  the  addition  of  sugar,  covered  the  tub  with  boards  and 
woollen  cloths,  and  left  it  to  ferment.  The  wine  cleared 
itself  through  the  vent  of  the  vat,  and  had  nearly  as  much 
strength  as  the  southern  wines,  whilst  that  which  had  been 
put  into  a  tub  without  the  addition  of  sugar  was  as  flat  and 
thick  as  the  coarse  red  wine  of  such  vintages  usually  is. 
The  last  kind  of  wine  usually  sells  for  fifty  francs  per  butt, 
and  I  have  refused  sixty-four  for  mine,  preferring  to  keep  it 
for  my  own  table.  The  wine  to  which  the  sugar  had  been 
added  was  as  clear  as  some  that  had  been  four  years  in  the 
cask,  and  was  much  more  agreeable  to  the  taste.  Twenty 
butts  of  wine  prepared  in  this  way  require  one  cwt.  of  sugar. 
The  mode  is  as  follows. 

As  soon  as  the  grapes  are  pressed  and  the  must  poured 
into  a  vat,  a  portion  of  the  same  liquid  is  put  into  a  boiler  and 
set  over  the  fire,  where  it  is  sufficiently  heated  to  dissolve 
the  sugar  i  as  soon  as  the  solution  is  completed  it  is  thrown 
into  the  vat,  and  the  whole  well  stirred :  this  operation  is  re- 
peated till  all  the  quantity  of  sugar  to  be  employed  is  com- 
bined with  the  liquor. 

Some  authors  advise,  that  the  must  itself  be  boiled  till  it 
is  reduced  to  one  half;  but  I  am  not  of  the  opinion  that  this 
is  the  best  mode  of  proceeding.  Boiling  reduces  a  portion 
of  the  vegeto-animal  principle  to  a  concrete  state,  and  thus 
affects  the  fermentation  of  the  liquor  :  I  have  always  lim- 
ited the  degree  of  temperature  to  which  the  must  should  be 
heated  to  35°  or  40°.*  In  the  northern  parts  of  France, 
where  grapes  never  ripen,  they  may  by  means  of  sugar  carry 
the  concentration  of  the  must  one  or  two  degrees  farther 
than  that  of  grapes  which  grow  in  the  best  years,  and  the 
wine  will  thus  be  rendered  far  richer  and  likewise  less  lia- 
ble to  decomposition. 

The  following  are  the  advantages  to  be  derived  fi-om  this 
method. 

[*  No  scale  is  mentioned  :  if  the  one  referred  to  be  the  centigrade, 
the  equivalent  numbers  upon  Fahrenheit's  are  95°  and  104°  y  if  Il6au- 
'ittur's,  110|°  md  122°.— Tr.} 


FERMENTATION.  243 

1st.  When  the  liquor  in  the  vat  is  heated  by  means  of  the 
solution  of  sugar,  the  temperature  is  raised  to  12°  or  14°,* 
and  this  causes  the  fermentation  to  take  place  more 
speedily. 

2d.  By  covering  the  vat,  the  liquor  is  secured  from  expe- 
riencing those  variations  of  atmospheric  temperature,  which 
may  either  hasten,  retard,  or  suspend  fermentation. 

3d.  The  heat  developed  in  a  close  vat  is  more  intense  than 
that  in  an  open  one,  and  the  decomposition  of  the  must  is 
consequently  more  perfect. 

4th.  The  addition  of  sugar  gives  rise  to  an  additional 
quantity  of  alcohol. 

5th.  The  head  of  the  liquor  is  much  less  apt  to  become 
sour. 

6th.  The  wine  is  more  equal  and  less  susceptible  of 
change. 

7th.  The  loss  of  alcohol  by  evaporation  is  less  than  in  un- 
tjovered  vats. 

As  next  to  that  of  corn  the  harvest  of  wine  is  the  most 
important  one,  inasmuch  as  it  forms  our  principal  article  of 
commerce  with  foreign  countries,  too  much  care  cannot  be 
taken  in  the  manufacture  of  it.t 

It  is  customary  with  most  of  our  proprietors  of  vine- 
yards to  plant  upon  the  same  soil  vines  of  diflerent  kinds 
of  grapes,  the  fruits  of  which  do  not  arrive  at  maturity  at 
the  same  time.  This  custom  is  particularly  practised  in 
those  vineyards  which  produce  wines  of  middling  quality ; 
and  it  has  been  introduced  and  continued  in  them,  because 
the  different  kinds  of  vines  do  not  flower  at  the  same  time, 
but  are  some  of  them  earlier  than  others,  and  some  of  them 
more  sensible  to  the  influence  of  the  changes   of  the  at- 


[*  If  the  centigrade  thermometer,  the  correspondinsr  deffrees  of  Fah- 
renheit's are  53.6°  and  57.2°  ;  if  Reaumur's  59°  and''63i^.  —  Tr.] 

t  The  mean  value  of  the  products  of  the  vineyards  of  France  from 
1805  to  1809,  was  about  36,000,000  hectolitres  of  wine,  {~  7,548,285 
pipes,  1  hhd.  27  gals.)  According  to  an  examination  afterwards  made 
b^  the  board  for  the  levying  of  indirect  duties,  which  claimed  some 
nght  over  this  liquor,  the  valuation  here  mentioned  is  believed  to  be 
far  short  of  the  truth. 

Vineyards  which  had  then  been  recently  planted,  and  consequently 
produced  but  little  wine,  now  afford  abundant  crops;  and  as  new 
ones  are  constantly  planted,  I  am  convinced  that  the  product  of  the 
vintage  is  very  considerably  augmented.  It  is  I  think  probable,  that 
the  harvest  of  wine  equcds  at  this  time  nearly  50,000,000  hectolitre*, 
<=  10,483>737  pipes,  1  lihd.  5  gals.) 


244  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

mosphere ;  it  therefore  rarely  happens  that  either  one  or  the 
©ther  does  not  bear.  This  mixture,  however,  in  the  same 
vineyard  is  injurious  to  the  quality  of  the  wine ;  for  although 
the  several  kinds  of  grapes  do  not  ripen  at  the  same  time, 
yet  they  are  all  harvested  together. 

Grapes  even  of  the  same  kind  do  not  all  ripen  at  the 
same  period ;  the  difference  of  exposure,  and  the  vegetative 
vigor  of  the  vine  advance  or  retard  the  ripening  several  days. 
By  gathering  them  all  at  once  and  subjecting  them  to  the 
same  fermentation,  the  wine  obtained  is  far  inferior  to  what 
it  would  be,  if  the  grapes  were  culled,  and  only  those  press- 
ed which  had  arrived  at  maturity. 

In  most  of  the  French  vineyards,  harvesting  is  commen- 
ced early  in  the  morning,  and  continued  throughout  the  day, 
till  the  vintage  is  ended ;  as  fast  as  the  grapes  are  brought 
in  they  are  pressed,  and  the  liquor  thrown  into  the  vat.  Now 
it  is  well  known,  that  grapes  when  moistened  with  dew  or 
rain  undergo  a  less  speedy  and  thorough  fermentation,  than 
when  thej  are  well  dried ;  and  it  is  likewise  an  established 
fact,  that  when  the  weather  is  hot  during  the  vintage,  the 
fermentation  of  the  grapes  is  not  only  more  rapid  but  better 
than  in  cooler  weather. 

It  appears,  then,  that  ijrapes  should  not  be  gathered  till 
the  heat  of  the  sun  has  dissipated  the  dew  j  it  is,  however, 
difficult  to  wait  for  all  the  favorable  circumstances  for  a  har- 
vest at  the  time  of  gathering  grapes  in  our  large  vineyards  ; 
they  can  only  be  seized  upon  for  the  manufacture  of  the 
most  delicate  and  costly  wines.  The  coarse  red  wines,  like 
those  from  the  banks  of  the  Loire  and  the  Cher,  are  sought 
for  in  commerce  only  in  proportion  to  the  depth  of  their 
color,  because  they  are  principally  used  for  mixing  with 
white  wines  :  the  new  wines  are  preferred  for  this  purpose, 
from  their  containing  a  portion  of  mucilage,  which  gives  to 
the  mixture  a  delicate  taste,  and  those  wines  which  have  lost 
this  principle  in  the  casks  are  rejected,  though  better  for 
drinking,  because  they  are  less  fit  to  be  mixed  with  dry 
white  wines. 

By  improving  the  fermentation  of  these  coarse  wines  they 
would  be  rendered  much  better  for  drinking  without  any 
mixture  ;  but  the  only  sale  there  is  for  them  would  be  closed, 
as  they  would  no  longer  be  bought,  as  they  are  now,  to  form, 
by  being  mixed  with  the  white  wine  of  Sologne,  the  princi- 
pal drink  of  the  people  of  Paris. 

In   some  wine  countries   it  is  customary  to  pluck  the 


FERMENTATION,  245 

grapes  from  the  stalks,  in  others  the  must  is  fermentea  with 
the  stalks  ;  the  mode  should  vary  according  to  the  nature  of 
the  grape,  and  the  use  for  which  t"he  wine  is  designed.  In 
the  south,  they  pluck  the  grapes  for  wine  that  is  destined  for 
the  table,  and  they  do  not  pluck  them  for  wine  which  is  to 
be  burned  or  distilled. 

M.  Labadie,  the  proprietor  of  a  vineyard,  and  a  very  en- 
lightened man,  states  that  the  wine  made  from  the  white 
grapes  of  Champagne  is  brisker,  and  less  likely  to  become 
oily,  when  made  of  fruit  that  has  not  been  plucked, 

Don  Gentil  is  convinced,  from  his  own  experience  in 
wine-making,  that  fermentation  proceeds  with  a  greater  de- 
gree of  energy  and  regularity  in  must  from  grapes  that  have 
not  been  plucked,  than  in  that  of  plucked  grapes. 

The  stalks  contain  a  slightly  bitter  principle,  which  is 
communicated  to  the  wine,  and  improves  the  taste  of  such 
as  is  naturally  flat,  and  at  the  same  time  fermentation  is 
facilitated  by  them.  According  to  this,  the  fruit  should  be 
separated  from  the  stalks  whenever  the  must  can  be  made, 
without  any  addition,  to  undergo  a  good  fermentation,  and 
produce  first-rate  wine ;  and  the  stalks  ought  not  to  be  re- 
moved from  such  grapes  as  usually  afford  only  an  ordinary, 
clammy  kind  of  wine,  which  does  not  keep  well.  Nor 
should  such  grapes  as  contain  a  large  portion  of  sugar  be 
separated  from  the  stalks,  as  they  will  then  produce  too 
sweet  a  wine. 

The  temperature  of  the  cellars  in  which  the  must  is  fer- 
mented is  seldom  equal  to  12''  of  Reaumur,  (=  59°  Fahr.) 
and  the  heat  of  the  atmosphere,  and  consequently  that  of 
the  grapes  does  not  often  indicate  that  degree ;  and  yet 
the  must  cannot  be  well  fermented  at  less  than  from  5*2°  to 
59^  Fahr.,  and  in  order  to  insure  a  perfect  fermentation  the 
heat  should  rise  thus  high. 

The  cellars  might  be  heated  by  stoves,  and  the  grapes 
placed  in  them  before  being  pressed,  till  they  had  acquired 
the  necessary  degree  of  warmth ;  or  what  would  be  better 
still,  the  must  might  be  heated  in  boilers  before  being  thrown 
into  the  vat ;  in  this  way  fermentation  would  take  place  in  a 
shorter  time,  and  be  more  lively  and  complete. 

As  soon  as  the  liquor  is  in  the  vat,  it  should  be  closely 
covered  over  with  boards  and  old  coverlids,  or,  in  prefer- 
ence, with  the  furniture  belonging  to  the  manufacture  of 
wine.  By  intercepting  all  communication  with  the  exter- 
nal air,  the  must  is  secured  from  being  affected  by  the 
21* 


246  CHYMISTRY   APPLIED    TO    AGRICULTURE, 

changes  of  temperature,  which  are  unfavorable  to  fermenta- 
tion, the  head  of  the  liquor  is  prevented  from  becoming  sour, 
and  at  the  same  time  a  constant  and  equable  heat  is  kept  up 
during  the  operation.  Should  the  fermentation  appear  to  re- 
lax, the  liquor  must  be  stirred  with  a  bough,  so  as  to  mix 
with  it  the  leaven  which  has  formed  upon  the  top,  and  by 
this  a  new  impulse  will  be  given  to  the  process.  Good  ef- 
fects arise  also  from  keeping  a  bough  of  the  vine  immersed 
in  the  liquor  by  means  of  boards  or  a  string. 

The  ancients  carefully  separated  all  the  various  juices 
which  they  could  obtain  from  grapes,  and  fermented  them 
singly  :  the  first,  which  was  procured  from  the  ripest  grapes 
by  the  slightest  pressure,  furnished  their  finest  wines,  called 
by  them  protopon,  mustum  sponte  defiuens  antequam  calccn- 
iur  uvm.  Baccius  describes  this  process  as  practised  by  the 
Italians,  thus  :  Qm/  primus  liquor,  non  calcatis  uvis,  dejluit, 
vinum  efficit  virgineum,  non  inquinatum  fmcihus  ;  lacrymam 
vacant  Itali ;  cito  potui  idoneum,  et  valde  utile. 

When  the  wine  has  fermented  sufficiently  in  the  vat,  it  is 
put  into  hogsheads,  and  there  undergoes  an  insensible  fer- 
mentation, which  completes  the  operations ;  by  being  kept 
undisturbed  it  settles  and  becomes  clear. 

In  those  countries  where  grapes  arrive  at  perfect  maturity, 
wine  can  be  kept  in  the  vat  in  which  it  is  fermented,  with- 
out any  danger  of  alteration  ;  and  this  is  done  in  most  of  the 
southern  cantons ;  it  is  however  necessary,  in  this  case,  that 
the  joinings  of  the  boards  with  which  the  vats  are  covered 
be  plastered  over  with  mortar,  that  the  air  may  not  gain  ad- 
mittance. 

Wine  makes  better  when  in  large  quantities  than  when 
divided  in  casks ;  but  in  those  countries  where  the  grapes 
contain  less  sugar,  and  where,  after  fermentation  in  the  vat, 
the  wine  still  contains  much  mucilage,  if  putting  it  into 
casks  is  delayed,  the  fermentation  will  very  soon  be  followed 
by  the  second,  and  the  product  of  this  last  is  vinegar :  the 
existence  of  alcohol  and  mucilage  is  sufficient  to  occasion 
this  change. 

The  casks  which  receive  the  wine  from  the  vat  should  be 
arranged  in  a  place  where  the  temperature  is  cool  and  uni- 
form, and  where  they  will  not  be  exposed  to  being  shaken  or 
jolted. 

When  fermentation  has  not  been  completed  in  the  vat, 
it  is  continued  in  the  casks,  and  all  the  principles  con- 
tained in  the  must,  which  are  not  susceptible  of  concurring 


FERMENTATION.  247 

in  the  fermentation,  are  either  precipitated  to  the  bottom,  or 
deposited  upon  the  sides.  All  the  methods  adopted  for  clar- 
ifying wine  are  founded  upon  this  principle.  The  mucilage, 
tartar,  and  extractive  matter  which  must  holds  in  solution, 
are  only  suspended  in  well-fermented  wine,  and  are  gradual- 
ly deposited  from  it.  The  burning  of  brimstone  in  the  casks 
facilitates  the  formation  of  the  deposit,  and  racking  sepa- 
rates the  deposited  matter  from  the  liquor.  By  the  addition 
of  isinglass  or  any  similar  substance  to  wine,  all  the  particles 
which  remain  suspended  in  it  are  seized  and  united  together, 
and  can  thus  be  removed. 

All  these  operations  tend  to  free  the  wine  from  foreign 
substances,  and  to  prevent  it  from  becoming  changed,  and  at 
the  same  time  to  preserve  all  the  taste  and  good  qualities 
which  belong  to  it.  The  red  wines  lose  a  part  of  their  col- 
oring matter  by  age,  and,  if  the  wine  has  been  well  clarified, 
this  change  can  be  accelerated  by  exposing  bottles  filled 
with  it  to  the  heat  of  the  summer's  sun.  In  this  case  the 
coloring  matter  is  precipitated  in  pellicles,  and  the  wine  be- 
comes of  the  color  of  an  onion  skin,  but  undergoes  no  other 
change :  I  have  seen  this  done  in  experiments  upon  the  best 
wines  of  Languedoc. 

When  wine  is  put  into  new  casks,  it  dissolves  a  portion 
of  the  tannin  and  extractive  matter  contained  in  the  wood, 
and  is  thus  colored  and  decomposed,  especially  if  the  wine 
be  not  very  strong.  The  liquor  in  this  case  acquires  what 
is  called  the  taste  of  the  cask.  The  color  which  brandy 
receives  in  the  cask  is  from  these  same  principles.  To 
obviate  this  inconvenience,  the  inside  of  the  hogsheads 
should  be  charred ;  the  wine  will  then  be  preserved  free  from 
alteration. 

The  most  common  degeneration  of  wine  is  its  becoming 
sour,  by  which  it  is  converted  into  vinegar  :  this  does  not, 
however,  take  place  if  the  wine  has  been  completely  freed 
from  the  mucilage  and  extract  contained  in  the  must,  but 
fermentation  is  seldom  thorough  enough  to  disengage  entire- 
ly, and  render  insoluble  these  principles,  especially  if  the 
grapes  are  not  well  ripened. 

This  degeneration  may  be  retarded,  and  even  prevented, 
by  keeping  the  liquor  in  closely  stopped  casks  set  in  a  cool 
place,  where  they  will  be  free  from  motion,  as  every  shake 
of  the  cask  mixes  again  with  the  wine  the  substances  which 
have  been  precipitated  from  it. 

The  acidification  or  acid  degeneration  does  not  take  place 


248  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

in  sweet  wine,  as  there  still  exists  in  that  a  portion  of  sugar 
which  renders  it  incapable  of  undergoing  any  other  than  the 
vinous  fermentation  ;  but  when  this  principle  is  entirely  de- 
composed, a  sufficient  degree  of  heat,  the  contact  of  the  at- 
mosphere, and  the  presence  of  a  little  mucilage  will  cause 
the  acidification  of  the  greater  number  of  wines. 

The  acid  degeneration  generally  takes  place  when  the 
grapes  do  not  contain  sugar  enough  to  decompose  all  the 
vegeto-animal  part :  it  occurs  necessarily  in  wine  which 
holds  in  solution  mucilage  and  extract ;  and  this  is  always 
the  case  when  the  sugar  contained  in  the  grapes  is  not 
sufficient  to  develope  much  alcohol,  and  precipitate  these 
substances. 

It  appears,  from  well-confirmed  experiments,  that  the  con- 
tact of  the  air  and  the  existence  of  mucilage  and  extract  in 
wine  containing  but  a  small  quantity  of  alcohol,  will  produce 
spontaneous  acidification. 

Stahl  states,  that  if  the  flowers  of  the  rose-tree,  or  the  lily 
of  the  valley  be  moistened  with  alcohol,  and  the  vase  con- 
taining them  shaken  occasionally,  vinegar  will  be  formed. 
He  likewise  informs  us  that  when  the  acid  of  lemon  is  satu- 
rated with  lime,  if  alcohol  be  thrown  upon  the  remaining 
portions  of  the  lemon  juice,  the  mixture,  when  exposed  to  a 
gentle  heat,  produces  vinegar. 

The  best  wine  may  be  converted  into  vinegar  by  soaking 
or  steeping  green  wood  in  it :  the  process  described  by  Boer- 
haave  is  founded  entirely  upon  this  principle :  he  employed 
for  the  purpose  the  branches  of  the  vine  and  the  stalks  of 
grapes. 

The  mash  of  grapes,  the  lees  of  wine,  and  the  residuum 
of  distillation  well  dried  and  moistened  with  a  little  alcohol 
and  water,  undergoes  the  acetous  fermentation.  The  juices 
of  most  other  fruits,  as  well  as  of  grapes,  may  be  made,  by 
fermentation,  to  produce  a  spirituous  liquor  to  be  used  either 
as  drink,  or  to  furnish  alcohol  by  distillation. 

The  practice  of  fermenting  various  kinds  of  bread  corn, 
particularly  rye  and  barley,  has  existed  for  a  long  time, 
and  from  them  are  produced,  by  distillation,  the  liquors 
that  are  most  used  in  those  countries  where  the  vine  is  not 
cultivated. 

Since  the  culture  of  the  potato  has  been  so  astonishing- 
ly extended  in  Europe,  the  uses  of  it  have  been  multiplied, 
and  it  is  now  fermented  for  the  purpose  of  obtaining  alco- 
hol by  distilldtion.     The   first  process  which  was  followed 


FERMENTATION.  249 

in  this  manufacture  is  still  practised  upon  the  banks  of  the 
Rhine,  and  in  Germany ;  by  the  second,  for  which  we  are 
indebted  to  modern  chymistry,  the  fecula  is  converted  into  a 
saccharine  substance,  and  thus  rendered  susceptible  of  the 
vinous  fermentation. 

I  shall  describe  concisely  both  of  these  processes,  because 
they  may  be  made  to  enter  advantageously  into  a  system  of 
labor  for  an  extensive  farm,  both  on  account  of  the  liquor 
obtained,  and  of  the  food  which  is  furnished  for  animals  by 
the  mash. 

The  old  method  may  be  reduced  to  the  two  following 
operations: 

A  cask  which  will  contain  about  two  English  hogsheads 
is  set  up  on  one  end,  and  a  square  opening  made  in  the 
head,  through  which  the  potatoes  are  thrown  in ;  another 
small  opening  is  formed  in  one  of  the  staves  on  a  level  with 
the  bottom  of  the  cask,  and  serves  for  taking  the  potatoes 
out.  The  potatoes  are  boiled  by  steam  introduced  into 
the  cask  by  a  tube  passing  through  the  lower  end  of  it. 
As  soon  as  the  potatoes  are  boiled,  they  are  crushed  as 
perfectly  as  possible  between  two  wooden  cylinders,  each 
of  which  is  furnished  at  one  end  with  a  driving  wheel,  put 
in  motion  by  a  crank.  The  pulp  of  the  potatoes  is  thrown 
into  a  tub  where  it  is  made  to  ferment :  the  vinous  fermen- 
tation would  not  however  take  place  in  it,  if  it  were  not  ex- 
cited by  the  addition  of  leaven  ;  the  leaven  used  is  made  in 
the  following  manner. 

To  4  pounds  of  malt  are  added  one  pint  of  beer  yeast, 
and  about  44  pounds  of  the  potato  pulp ;  these  are  worked 
carefully  together  and  diluted  with  ten  or  eleven  gallons 
of  water  at  the  temperature  of  40°  Reaumur,  (=:  122° 
Fahrenheit,)  and  the  vessel  containing  the  mixture  is  cov- 
ered over.  The  paste  thus  made  ferments  and  rises,  and 
at  the  end  of  twenty-four  hours,  it  is  mixed  with  the  body 
of  pulp  deposited  in  the  vat,  some  hot  water  is  thrown  in 
upon  it,  and  the  whole  is  stirred  constantly,  till  the  tem- 
perature of  the  liquid  stands  at  from  15°  to  18°  Reaumur, 
(zzz  to  65f°  and  72^°  Fahrenheit,)  and  the  specific  gravity 
marks  6°  or  7°  upon  the  aerometer,  (=1  specific  gravity  of 
1.044  to  1.052.) 

During  fermentation,  care  must  be  taken  that  the  tem- 
perature of  the  place  should  not  vary  more  than  from  20° 
to  25°  Reaumur,  (=  to  77°  and  88°  of  Fahrenheit ;)  and 
without  this  the  fermentation  will  lansfuish  and  never  be 


250  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

complete.  When  all  circumstances  are  favorable,  the  fer- 
mentation may  be  terminated  the  third  day,  but  it  is  most 
commonly  prolonged  till  the  fourth  or  fifth. 

If  the  operation  be  well  conducted,  the  fermented  liquor 
will  mark  only  0  to  1°  of  the  aerometer,  {=z  specific  gravity 
of  1.000  to  1.007;)  the  more  complete  the  fermentation  is, 
the  less  will  be  the  specific  gravity  of  the  liquor. 

This  action  should  never  be  violent,  as  it  is  well  known 
that  in  such  cases  the  product  is  less  than  when  it  is  slow 
and  regular  :  whilst  it  is  going  on,  all  the  fragments  of  the 
potatoes  rise  to  the  top  and  form  a  crust,  which  must  be 
separated  towards  the  middle  to  allow  of  the  escape  of  the 
gas. 

In  a  manufactory  where  the  processes  are  constantly  going 
on,  it  is  not  necessary  to  form  a  new  ferment  for  each  opera- 
tion ;  about  three  gallons  may  be  reserved  to  be  made  use 
of  when  again  required. 

Distillation  should  be  so  conducted,  that  the  alcohol  may 
pass  off  equally  and  regularly,  and  this  can  only  be  done  by 
a  judicious  management  of  the  fire :  the  variations  of  the 
heat  applied  to  the  boiler  accelerate  or  retard  distillation, 
and  consequently  the  alcohol  in  these  two  cases  is  not  pro- 
duced in  the  same  degree :  it  often  happens  when  the  fire  is 
too  forcible,  that  the  liquid  contained  in  the  boiler  is  itself 
forced  into  the  worm  of  the  still. 

It  is  of  importance  in  a  distillery  to  have  an  abundance  of 
water,  both  that  the  casks  may  be  thoroughly  rinsed  after 
each  operation,  and  for  cooling  the  worm  of  the  still,  as  with- 
out this  precaution  a  portion  of  the  alcohol  formed  would  be 
lost  by  evaporation. 

By  this  method  four  sacks  of  potatoes  yield  upon  an  aver- 
age 13  gallons  and  a  fraction  of  brandy,  at  20°  (=  specific 
gravity  of  0.935,)  of  the  aerometer ;  if  all  circumstances 
are  favorable,  they  may  afford  15  gallons. 

When  wines  are  dear  and  potatoes  cheap,  the  manufac- 
ture of  brandy  in  this  method,  is  found  very  profitable :  in 
the  year  1816,  the  advantages  arising  from  it  were  very  great, 
and  even  under  ordinary  circumstances,  it  may  be  done  with 
profit. 

The  residuum  of  the  distillation,  mixed  with  mustard  or 
turnip  cakes,  forms  excellent  food  for  horned  cattle,  and  is 
eaten  by  them  with  avidity. 

The  fecula  or  starch  of  potatoes  was  first  converted  into 
a  fermentable  saccharine  substance  by  M.  Kirchoff,  of  St, 


FERMENTATION.  ^1 

Petersburgh  ;  it  was  done  by  means  of  boiling  it  a  long  time 
in  a  weak  sulphuric  acid  ;  the  result  has  been  seized  upon, 
and  made  the  basis  of  an  advantageous  mode  of  rendering 
fecula  fermentable,  and  extracting  from  it  a  spirituous  liquor. 
This  process  has  been  brought  to  such  a  perfection  in  France, 
that  the  products  of  the  establishments  sustain  a  competition 
with  those  of  wine  and  brandy,  though  the  latter  may  be 
selling  in  commerce  at  a  low  rate. 

The  first  step  is  to  mix,  in  a  leaden  boiler,  concentrated 
sulphuric  acid  with  water,  in  the  proportion  of  3  of  acid  to 
100  of  water:  the  temperature  of  the  liquor  is  then  raised 
to  boiling,  and  the  fecula  is  ijiade,  by  means  of  a  hopper, 
to  fall  gradually  into  it :  the  mixture  is  then  stirred  forci- 
bly and  the  boiling  at  the  same  time  continued.  After  six 
hours  the  ebullition  is  stopped ;  the  acid  is  then  saturated 
with  chalk,  and  a  sulphate  of  lime  is  thus  formed  and  quick- 
ly precipitated. 

When  all  the  deposit  has  formed,  and  the  liquor  become 
clear,  it  is  carefully  racked  off  and  thrown  into  the  vats  in 
which  it  is  to  be  fermented.  These  vats  are  five  feet  deep 
and  four  and  a  half  in  diameter  ;  they  are  situated  in  a  place 
where  they  can  be  kept  constantly  at  a  temperature  of  from 
77°  to  88^°  Fahrenheit. 

The  density  of  the  liquor  should  be  from  7°  to  8°  of  the 
aerometer,  (=  specific  gravity  of  1.052  to  1.060.)  As  soon 
as  the  fermentable  liquor  has  acquired  the  temperature  of  the 
distillery,  there  is  mixed  with  it  44^  lbs.  of  the  beer  yeast 
which  is  brought  from  Holland :  fermentation  takes  place  in 
a  short  time  and  continues  several  days ;  it  sometimes  re- 
laxes in  energy,  but  in  a  few  days  the  action  is  renewed  with 
increased  activity. 

1  cwt.  of  potatoes  ought  to  yield  from  5^  to  6^  gallons,  and 
this  will  be  the  case  when  the  process  is  well  conducted. 
Starch  sells  in  Paris  at  from  8  to  9  francs  (=  about  144  and 
171  cents)  per  cwt. 

This  brandy  has  neither  a  bad  taste  nor  odor,  and  the 
manufacturers  of  liquors  prefer  it  to  that  made  from  wine. 


252  CHYMISTRY   APPLIED    TO    AGRICULTURE. 

CHAPTER    XVI. 

OF    DISTILLATION. 

The  art  of  distilling  wine  to  extract  from  it  the  spirituous 
principle,  has  made  known  a  new  product,  which  is  used  not 
only  as  drink,  but  as  one  of  the  most  useful  articles  employ- 
ed in  the  arts. 

The  product  of  the  distillation  of  wine  is  known  in  com- 
merce under  the  names  of  brandy,  alcohol,  spirit  of  wine, 
&c.  and  the  apparatus  in  which  the  process  is  carried  on  is 
called  an  alembic* 

The  importance  of  vineyards  has  been  greatly  increased 
by  the  discovery  of  the  art  of  distilling  wine ;  before  that 
the  vine  was  cultivated  for  no  other  purpose  than  that  of  fur- 
nishing a  strengthening  and  agreeable  drink :  distillation 
disengages  from  this  liquor  a  volatile,  inflammable,  spirit- 
uous principle,  forming  a  much  more  active  drink  which  has 
come  into  general  use  throughout  nearly  all  Europe ;  it  is 
likewise  used  in  the  arts  for  dissolving  resins  and  forming 
varnishes,  to  preserve  fruits,  dissolve  the  perfumes  of  plants, 
and  to  establish  some  new  processes. 

Most  of  the  white  and  a  part  of  the  red  wines  are  now 
employed  for  distillation  :  the  good  red  wines  are  reserved 
for  the  table. 

Before  quitting  so  important  a  subject,  I  will  sketch,  in  a 
few  words,  all  which  had  been  done  in  the  way  of  distilling 
wine  before  the  invention  of  the  new  apparatus,  which  has 
caused  such  a  revolution  in  the  art  of  distillation,  that  it  may 
be  said  to  have  been  created  at  the  present  day. 

The  ancients  had  very  imperfect  ideas  of  distillation. 
From  the  evidence  of  Raymond  Lully,  Jerome  Rubeus, 
and  John-Baptist  Porta,  there  can  be  no  doubt,  that  the 
ancients  understood  the  art  of  extracting  the  odoriferous 
principle  by  the  steam  from  water ;  but  they  made  use  of 

*  The  names  brandy  and  spirit  of  wine,  employed  to  designate  the 
two  extremes  of  the  same  liquor  as  they  are  found  in  commerce, 
have  been  supplied  in  the  new  chymical  nomenclature  by  the  generic 
term  alcohol.  However,  as  in  common  language  the  names  brandy 
and  spirit  of  wine  are  given  to  substances  differing  widely  in  the  uses 
to  which  they  are  applied,  it  is  to  be  feared  that  commerce  will  not  be 
willing  to  comprehend  them  under  the  same  denomination ;  as  it  is 
not  enough  that  they  are  of  the  same  nature,  if  the  price  and  the  use 
establish  a  wide  difference  between  them. 


DISTILLATION.  253 

nothing  which  deserved  the  name  of  apparatus.  Dioscorides 
says,  that  in  distilling  resin  it  is  necessary  to  collect  the  vola- 
tile particles  upon  cloths  placed  over  the  vase. 

The  first  navigators  of  the  islands  of  the  Archipelago 
procured  fresh  water  by  receiving  the  vapor  of  salt  water  in 
sponges  arranged  upon  the  vessels  in  which  it  was  boiled. 
(See  Porta,  Dc  Distillatione,  Cap.  I.) 

The  word  distillation  did  not  possess,  amongst  the  an- 
cients, any  signification  analogous  to  the  import  of  it  at  the 
present  time :  it  was  used  by  them  as  a  generic  term,  com- 
prehending filtration,  fluxation,  sublimation,  and  all  the  sim- 
ilar operations  to  which  we  have  assigned  various  names,  and 
for  each  of  which  we  use  a  particular  kind  of  apparatus, 
(Jerome  Rubeus,  De  Distillatione.) 

During  the  time  of  the  republic  and  under  the  reign  of 
the  kings,  the  Romans  appear  to  have  known  nothing  of 
distilled  spirit :  Pliny,  who  wrote  during  the  first  century 
of  the  Christian  era,  makes  no  mention  of  it ;  he  has  left 
us  a  very  good  treatise  upon  vinegar  and  wine,  but  he  says 
nothing  of  distilled  liquor,  though  he  speaks  of  wine  in 
all  its  forms :  Galen,  who  lived  a  century  after  him,  uses 
the  word  distillation  in  the  sense  which  I  have  mentioned 
before. 

The  art  of  distillation  in  all  probability  owes  its  origin  to 
the  Arabians,  who  have,  from  time  immemorial,  formed  ex- 
tracts of  the  aroma  of  plants,  and  who  brought  their  modes 
of  proceeding  successively  into  Italy,  Spain,  and  the  south 
of  France :  it  even  appears  that  the  word  alembic  is  found 
for  the  first  time  in  their  writings,  and  has  its  origin  in 
their  language ;  it  was  used  by  them  before  the  tenth  centu- 
ry ;  for  Avicenna,  who  lived  at  that  time,  made  use  of  it  to 
explain  the  nature  of  the  disease  called  catarrh,  which  he 
compared  to  a  distillation  in  which  the  stomach  is  the  cucur- 
bite,  the  head  the  cap,  and  the  nose  the  beak  by  which  the 
humors  flow  out. 

Rhazes  and  Albucazin  describe  particular  processes  for 
extracting  the  aromatic  principle  from  plants  ;  it  appears  that 
the  steam  was  generally  received  into  the  cap  of  the  still, 
which  was  cooled  by  wet  cloths. 

It  is  evident  that  Raymond  Lully,  who  lived  in  the  thir- 
teenth century,  was  acquainted  with  distilled  spirit  and 
alcohol,  for  in  his  work  entitled  Test  amentum  novissimum, 
at  page  2d  of  the  Strasburg  edition,  1571,  he  says  :  "  Re- 
cipe nigrum  nigrius  nigro  (red  wine)  et  distilla  totam 
22 


254  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

aquam  ardentem  in  balneo ;  illam  rectificabis  quousque 
sine  phlegmate  sit."  He  states  that  seven  rectifications  are 
employed,  but  that  three  are  sufficient  to  render  the  alco- 
hol inflammable,  and  to  prevent  its  leaving  any  aqueous 
residuum. 

The  same  author  shows  elsewhere  the  mode  of  separating 
the  water  by  means  of  a  dry  fixed  alkali.  (See  Bergman's 
Opuscula  physica  et  chi/mica,lue'vps\c  edition  of  1781,  Vol. 
IV.  page  137.)  Towards  the  end  of  the  fourteenth  century, 
Basil  Valentine  proposed  the  use  of  quicklime  for  the  same 
purpose. 

In  all  his  works  Raymond  Lully  speaks  of  a  preparation 
of  distilled  spirit  which  he  calls  quinta  essentia,  whence  is 
derived  the  word  quintessence :  he  obtained  it  by  repeated 
cohobations  made  at  a  gentle  heat  during  several  days,  and 
by  redistilling  the  product.  Raymond  Lully  and  his  suces- 
sors  attached  great  virtue  to  this  quintessence,  which  they 
made  the  base  of  all  their  alchymical  labors. 

Arnold  of  Villanova,  a  contemporary  of  Lully,  speaks 
much  of  distilled  spirit,  but  not  in  such  a  manner  as  to  jus- 
tify the  conclusion  of  his  being  the  inventor  of  the  process 
by  which  it  was  obtained ;  he  cannot  however  be  denied  the 
honor  of  having  made  the  happiest  application  of  the  proper- 
ties of  distilled  spirit,  and  particularly  of  simple  and  com- 
pounded wine,  both  in  medicine  and  pharmaceutical  prepa- 
rations. (Arnaldi  Villanovani  Praxis :  Tractatus  de  Vino ; 
cap.  De  Potibus,  etc.;  edit.  Lugduni,  1586.) 

Michael  Savonarola,  who  lived  at  the  commencement  of 
the  fifteenth  century,  has  left  us  a  treatise  (De  conjiciendd 
Aqua  Vit(B,)  which  contains  some  very  remarkable  things 
respecting  distillation.  He  first  remarks,  that  those  who 
preceded  him  did  not  generally  know  the  following  process 
for  distillation.  This  process  consists  in  putting  the  wine 
into  a  metal  boiler,  and  receiving  the  vapor  in  a  pipe  placed 
in  a  bath  of  cold  water ;  the  condensed  vapor  flowed  from 
the  pipe  into  a  receiver. 

Savonarola  observes,  that  distillers  placed  their  establish- 
ments near  a  stream  of  water,  that  they  might  always  have 
fresh  water  at  their  disposal.  The  ancients  called  the  spiral 
worm  of  the  still  vitis,  on  account  of  its  windings.  (See 
Jerome  Rubeus.)  For  closing  the  joinings  of  the  apparatus, 
they  employed  a  lute  made  of  lime  and  white  of  eggs ;  or 
one  of  flour  paste  and  paper. 

Savonarola  adds,  that  in  his  day  the  use  of  glass  cucur- 


DISTILLATION.  255 

bites  was  introduced,  that  the  distilled  spirit  might  be  more 
pure  ;  and  that  they  were  covered  with  a  cap  which  was 
cooled  with  wet  cloths.  He  advises  the  use  of  large  caps,  as 
increasing  the  surface.     (Cap.  V.) 

The  same  author  says,  that  the  neck  uniting  the  boiler 
and  the  head  should  be  as  long  as  possible,  in  order  that  the 
spirit  may  be  produced  at  once,  and  adds,  that  one  of  his 
friends  placed  the  boiler  on  a  level  with  the  ground,  and  the 
cap  upon  the  roof  of  the  house. 

Amongst  the  various  means  which  he  gives  us,  by  which 
we  may  judge  of  the  degrees  of  strength  of  distilled  spirit, 
he  mentions  the  following  as  being  practised  in  his  time. 
1st.  Cloth  or  paper  is  dipped  in  the  liquor,  and  then  set  on 
fire ;  if  the  flame  of  the  liquor  burns  the  cloth  or  paper,  the 
liquor  is  said  to  be  of  a  good  quality.  2d.  The  liquor  is 
mixed  with  oil  to  see  if  it  will  swim. 

Savonarola  treats  at  length  of  the  virtues  of  distilled  spir- 
it, and  gives  some  processes  for  combining  with  it  the  aroma 
of  different  plants  and  some  other  principles,  both  by  mace- 
ration and  by  distillation,  and  for  thus  making  what  he  calls 
aqua  ardens  composita. 

Jerome  Rubeus,  who  made  many  experiments  in  the  way 
of  distillation,  describes  two  very  curious  processes,  which 
he  found,  in  fact,  in  ancient  works  :  one  of  these  processes 
consisted  in  receiving  the  steam  into  long,  twisted  tubes 
plunged  in  cold  water ;  the  other,  in  placing  over  the  cucur- 
bite  a  cap  of  glass,  with  a  beak.  It  is  remarkable  that  Je- 
rome Rubeus  preferred  the  apparatus  with  the  long  tube,  as 
he  obtained  by  it,  with  a  single  distillation, -very  pure  spirit 
of  wine,  which  could  only  be  obtained,  with  the  other  kind, 
by  repeated  distillations.  {De  Distillatione,  §  ^,  cap.  II. 
edit,  de  Bale,  de  1568.) 

John-Baptist  Porta,  a  Neapolitan,  who  lived  towards  the 
end  of  the  sixteenth  century,  published  a  treatise,  De  Dis- 
tillationibus,  in  which  he  viewed  the  operation  in  all  its 
connections,  and  as  applied  to  all  the  substances,  which  are 
capable^  of  undergoing  it ;  he  described  the  different  kinds 
of  apparatus  by  which  there  might  be  obtained  at  pleasure, 
and  by  a  single  heat,  distilled  spirit  in  all  its  degrees  of 
strength. 

The  first  kind  of  apparatus  consists  of  a  tube  twisted 
spirally,  and  fitted  to  the  top  of  the  boiler ;  the  second  is 
composed  of  caps  placed  one  over  the  other,  each  one 
being  furnished  with  an  opening   in  the  side,  to  which  w 


25Q  CHYMISTRY    APPLIED    TO    AGRICULTURE^ 

fitted  a  tube  communicating  with  the  receiver ;  he  observes-, 
that  by  this  means  there  can  be  obtained  at  pleasure  all  the 
degrees  of  rectification,  since  the  aqueous  particles  are  con- 
densed in  the  lower  caps,  whilst  the  spirituous  parts  rise  to 
the  upper  one.  These  methods  differ  very  little  from  thos6 
which,  according  to  Jerome  Rubeus,  were  in  use  among  the 
ancients. 

Nicholas  Lefebvre,  who  lived  towards  the  middle  of  the 
seventeenth  century,  published,  in  1651,  a  description  of  the 
apparatus  with  which  he  obtained,  at  a  single  operation,  the 
purest  alcohol. 

This  apparatus  is  composed  of  a  long  funnel  formed  of 
several  pieces  joined  together  in  zigzags;  one  end  of  it  is 
fitted  to  the  boiler,  and  the  other  to  the  cap  ;  the  beak  of  the 
cap  transmits  the  vapor  into  a  pipe,  which  passes  through  a 
cask  filled  with  cold  water ;  in  this  pipe  the  vapor  is  con- 
densed and  flows  from  it  into  a  receiver. 

Dr.  Arnaud,  of  Lyons,  in  his  Introduction  d  la  Chimie 
ou  a  la  vraie  Phi/siquCy  ikprime  en  1655,  chez  CL  Prost, 
a  Lyon,  has  given  us  some  excellent  instructions  in  re- 
gard to  the  construction  of  furnaces,  the  composition  of 
ffues,  •  the  mode  of  regulating  the  fire,  calcination,  and 
distillation,  which  he  calls  a  moist  sublimation.  He  advises 
the  use  of  shallow  boilers  as  facilitating  evaporation ;  he 
speaks  of  the  conversion  of  distilled  spirit  into  the  spirit 
of  wine,  by  repeated  distillations  in  a  water  bath,  such  as 
is  now  employed  for  distilling  those  substances,  the  spirit- 
uous portions  of  which  are  vaporized  at  a  degree  of  heat 
less  than  that  of.  boiling  water.  He  also  speaks  of  the  vapor 
or  dew  bath. 

John  Rodolph  Glauber,  in  his  treatise  entitled  Dc- 
scriptio  Artis  Distillatorim  novce,  printed  in  Amsterdam 
in  1658,  by  John  Janson,^  makes  known  to  us  some  pro- 
ceedings, in  which  we  find  the  germ  of  most  of  the  opera- 
tions, which  are  now  carried  to  such  perfection  amongst 
us.  One  of  them  consists  in  transmitting  the  vapor 
which  escapes  by  distillation  into  a  vase  surrounded  with 
cold  water  :  the  vapor  which  is  not  condensed  in  this  first 
vessel,  passes  through  a  bent  tube  into  a  second,  from  that 
to  a  third,  and  so  on  till  the  whole  is  perfectly  condensed. 
It  is  evident,  that  by  means  of  such  an  apparatus,  spirits 
of  wine  of  different  degrees  of  rectification  may  be  ob- 
tained, according  as  the  condensation  takes  place  in  the 
first,  second,  or  third  of  the  vases,  plunged  in  cold  watef. 


DISTILLATION.  257 

In  another  kind  of  apparatus,  he  placed  a  retort  of  copper 
in  a  furnace ;  the  beak"  of  the  retort  passed  into  a  close  cask 
filled  with  the  liquor  which  he  wished  to  distil ;  a  tube,  fitted 
into  the  upper  part  of  the  cask,  was  joined  to  a  worm  placed 
in  another  cask,  which  was  filled  with  cold  water.  By  this 
arrangement,  the  liquid  contained  in  the  first  cask  was  con- 
tinually falling  into  the  retort,  where  it  was  heated,  and  thus 
the  whole  contents  of  the  cask  were  at  length  raised  to  a 
sufficient  degree  of  heat  to  produce  distillation,  and  thus  a 
considerable  volume  of  liquor  was  heated  with  a  small  fur- 
nace, and  at  a  trifling  expense.  Glauber  applied  this  ingey 
nious  apparatus  to  heating  baths. 

Philip  James  Sachs,  in  a  work  printed  at  Leipsic,  in  1661, 
under  the  title  of  Vitis  vinifer(£  ejusque  Partium  Consider  a- 
tio,  &i>Q,.,  has  given  us  a  complete  and  very  valuable  treatise 
upon  the  culture  of  the  vine,  the  nature  of  the  soils,  cli- 
mates, and  exposure  adapted  to  the  growth  of  it ;  the 
manner  of  making  wine;  the  comparative  wealth  of  differ- 
ent nations  in  this  article  of  culture ;  the  differences  and 
resemblances  of  the  several  methods  used  amongst  each 
of  them  ;  the  distillation  of  wines,  &c.  In  the  last  chapter 
we  see  what  will  only  detain  us  for  a  moment,  that  the  an- 
cients had  many  methods  of  extracting  spirit  of  wine, 
and  that  these  consisted  entirely  either  in  vaporizing  it  at 
a  gentle  heat,  depriving  wine  of  its  water  by  calcined  alum, 
putting  moistened  cloths  over  the  alembic,  placing  ice  upon 
the  cap  of  the  alembic,  that  the  most  subtle  vapors  might 
not  escape,  or,  finally,  in  terminating  the  boiler  by  a  very 
long  neck. 

The  same  author  speaks  also  of  the  quintessence, 
quinta  essentia,  and  gives  various  modes  of  extracting  it. 
"  Ut  vero  spiritus  vini  alcool  exaltetur,  variis  modis  tenta- 
runt  chimici ;  quidam  multis  repetitis  cohobationibus  ;  ali- 
qui,  instrumentorum  altitudine;  alii,  spongia  alambici  ros- 
trum obturante,  ut,  aqua  retenta,  soli  spiritus  transirent; 
non  multi,  flamma  lampadis,  ut  ad  summum  gradum  depu- 
rationis  exaltaretur." 

Moses  Charas,  in  his  Pharmacopcdia,  printed  in  1676, 
describes  the  apparatus  of  Lefebvre,  and  adds  some  im- 
provements to  it ;  he  adapts  a  refrigerator  to  the  cap.  We 
may  still  see,  in  the  Elemens  de  Chimie  of  BerchusenJ 
printed  in  1718,  and  in  those  of  Boerhaave,  which  appeared 
at  Paris  in  1733,  several  processes  detailed,  by  which  very 
pure  alcohol  may  be  obtained  at  a  single  distillation;  but 
22* 


258  CHYMISTRY   APPLIED   TO    AGRICULTURET, 

in*  all  of  them  the  vapor  passes  through  long  tubes,  that 
the  aqueous  particles  may  be  condensed,  and  that  the  'last 
fesult  may  not  be  received  till  it  is  as  light  and  pure  as 
possible. 

Subsequently  to  these  authors,  many  others  have  written 
upon  the  subject  of  distillation,  and  have  proposed  and 
executed  many  alterations  upon  their  methods ;  instead, 
however,  of  improving  upon  the  happy  idea  of  their  pred- 
ecessors, who  aimed  at  obtaining  at  pleasure  all  the  de- 
grees of  alcohol  by  successive  condensations  of  the  watery 
particles  mixed  with  the  alcohol,  they  confined  themselves 
to  varying  the  form  of  the  boiler,  the  retort,  or  the  worm, 
and  thus  the  art  of  distilling  was  nearly  in  a  retrograde  state 
for  almost  a  century. 

This  art  was  stationary  a  short  time  since,  when  a  process 
was  generally  adopted,  which,  though  far  from  being  found- 
ed upon  true  principles,  produced  the  desired  effect.  In  this 
process  the  alcohol  of  the  different  degrees  of  strength  was 
obtained  by  repeated  distillations.  Such  was  the  state  of 
the  art  towards  the  end  of  the  last  century ;  at  that  period 
the  apparatus  most  generally  employed  for  distilling  was 
composed  of  three  pieces ;  the  metal  used  was  copper ; 
the  boiler,  which  contained  about  50  gallons  of  wine,  was 
contracted  in  size  towards  the  upper  pmrt ;  a  cap  was  adapt- 
ed to  the  orifice,  and  communicated  by  a  long  pipe  with  a 
worm  ;  the  worm  was  placed  in  a  cask  which  was  kept  full 
of  cold  water,  and  thus  condensation  of  the  alcoholic  vapor 
was  produced. 

This  coarse  apparatus  possessed  many  defects,  the  first 
of  which  was,  that  all  the  vapors  raised  by  the  action  of 
the  fire  passed  into  the  worm,  where  they  were  condensed  ; 
thus  the  aqueous  particles  were  mixed  with  those  of  alco- 
hol, and  flowed  with  them  into  the  receiver,  forming  a 
weak  distilled  spirit,  which  required  to  be  submitted  to  a 
second  distillation  before  it  could  be  brought  to  a  due  degree 
of  strength. 

The  second  inconvenience  arising  from  this  apparatus, 
was  the  incompleteness  of  the  condensation;  for  as  the 
water  in  the  cask  soon  became  heated,  there  consequently 
ensued  a  great  loss  of  alcoholic  vapor,  which  passed  off 
'into  the  atmosphere  of  the  distillery. 

The  third  fault  was,  that,  as  all  the  vapors,  which  rose 
from  the  boiler,  passed  immediately  into  the  worm,  where 
they  were  condensed,   it  was  necessary  so  to  regulate  the 


DISTILLATION.  259 

fire,  that  the  alcoholic  particles  alone  might  be  evaporated ; 
a  few  moments  of  too  great  heat  were  sufficient  to  cause 
the  ascension  of  a  great  mass  of  aqueous  vapor,  by  which 
the  alcohol  was  rendered  deficient  in  strength  ;  the  necessi- 
ty of  watching  the  fire,  therefore,  made  the  operation  a  very 
difficult  one. 

The  union  of  so  many  faults  in  the  apparatus,  rendered  it 
impossible  to  extract  the  last  portions  of  alcohol  remaining 
in  the  wine,  without  their  being  loaded  with  an  immense 
quantity  of  aqueous  particles :  this  last  product  of  distillation 
was  carefully  separated  under  the  name  of  small  water ^  and 
redistilled  with  a  new  portion  of  wine. 

The  spirit  obtained  by  the  above  process  always  has  a 
burnt  taste,  and  is  rarely  very  clear ;  this  arises  from  the 
difficulty  of  regulating  the  fire,  and  the  still  greater  difficul- 
ty of  obtaining,  without  increasing  the  heat  too  much,  all 
the  alcoholic  particles  contained  in  the  wine. 

If  to  the  above-mentioned  faults  we  add,  that  the  furnaces 
of  these  alembics  were  badly  constructed,  that  they  present- 
ed no  means  either  of  regulating  the  heat,  or  of  applying  it 
equally  to  the  whole  body  of  the  liquor,  we  shall  see  that  the 
art  of  distilling  was  yet  in  its  infancy. 

I  was  aware  of  these  defects,  and  attempted  to  correct 
them,  and  in  consequence  I  caused  to  be  made  large  boilers 
of  but  little  depth,  that  as  great  a  surface  as  possible  might 
be  presented  to  the  fire ;  I  surrounded  the  cap  with  a  bath  of 
cold  water ;  this  produced  the  first  condensation,  and  separa- 
ted the  aqueous  particles,  which  fell  back  in  drops  or  streams 
into  the  boiler ;  I  increased  the  number  of  windings  in  the 
worm,  and  enlarged  the  bath-cask,  that  the  water  might  not 
80  soon  become  heated.  These  alterations  were  approved  of, 
and  distillation  was  established  upon  these  principles.  My 
apparatus  and  that  of  M.  Argand,  who  had  wonderfully  inri- 
proved  the  furnace,  was  employed  with  success  during  fifl;een 
or  twenty  years. 

In  the  first  years  of  the  present  century,  the  art  of  distilla- 
tion was  established  upon  new  principles,  and  it  has  gone  far 
beyond  all  that  was  before  known  and  practised.  A  chymi- 
•cal  apparatus,  by  means  of  which  vapors  or  gases  were  made 
to  pass  through  liquids  which  were  to  be  saturated  with  them, 
gave  to  Edward  Adam  the  first  idea  of  his  apparatus  for  dis- 
tillation ;  a  knowledge  of  the  fact  that  aqueous  vapors  are 
condensed  at  a  degree  of  heat  which  does  not  effect  a  like 
change  in  alcoholic  vapor,  fiirnished  hira  with  the  means  of 
completing  his  apparatus. 


260  CHYMISTRY   APPLIED    TO    AGRICULTURE. 

The  chymical  apparatus  suggested  to  Adam  the  idea  of 
conducting,  by  the  aid  of  a  copper  tube,  the  vapor  which 
rises  from  a  boiler  of  wine  placed  over  the  fire  of  a  fur- 
nace, into  a  second  boiler  of  the  same  liquid,  which  is 
thus  heated  to  the  boiling  point :  the  vapor  from  this  second 
boiler  may  be  carried  into  a  third,  in  which  ebullition  will 
likewise  take  place ;  and  thus  by  means  of  a  fire  kept  under 
one  boiler,  distillation  may  be  carried  on  in  two  or  three, 
provided  they  are  well  closed.  This  mode  of  transmitting 
heat  is  now  practised  in  most  foreign  distilleries,  and  it  is 
called  heating  hy  steam. 

Edward  Adam,  by  the  process  just  detailed,  made  a 
great  saving  of  fuel,  and  was  sure  that  the  spirit  obtained 
would  always  be  free  from  a  burnt  taste.  He  also  saved 
time  and  labor,  for  the  workman  whose  business  it  was  to 
attend  one  furnace,  accomplished  much  greater  results, 
than  if  that  fire  caused  the  evaporation  of  but  one  boiler. 
These  were  certainly  great  improvements,  but  it  was 
necessary  to  go  still  further,  and  to  find  the  means  of  ob- 
taining alcohol  in  its  greatest  possible  purity  by  freeing  it 
from  all  aqueous  particles,  and  this  he  did  by  applying  to 
his  apparatus  the  second  principle  which  we  have  already 
specified.  "  By  making,"  he  says,  "  the  alcoholic  vapor 
which  rises  out  of  the  last  boiler  pass  into  vessels  im- 
mersed in  a  bath  of  cold  water,  the  aqueous  vapor  will  be 
condensed,  and  I  can  then  bring  it  back  again  into  the 
first  boiler,  to  be  there  redistilled,  whilst  the  alcoholic  va- 
por will  pass  out  of  these  vessels,  without  being  con- 
densed, into  the  worm,  where  it  will  undergo  condensa- 
tion." 

Proceeding  upon  this  reasoning,  founded  upon  positive 
facts,  he  adapted  a  tube  to  the  upper  part  of  the  last  boiler ; 
this  tube  conducts  the  vapor  into  a  first  condenser,  which  is 
of  a  spherical  form  and  immersed  in  a  water  bath ;  in  this, 
a  part  of  the  aqueous  vapors  are  resolved  into  a  liquid  form, 
and  this  liquid  is  carried  by  a  pipe  into  the  wine  of  the  first 
boiler,  to  be  redistilled  and  deprived  of  the  small  portion  of 
alcohol  which  it  still  holds  in  solution ;  the  vapors  which 
cannot  be  condensed  in  the  first  receiver  pass  into  a  second, 
where  a  new  condensation  takes  place  in  consequence  of 
the  temperature  being  less  elevated;  from  the  second  it 
goes  into  a  third,  and  thence  into  a  fourth ;  that  which  is 
condensed  returns,  as  I  have  just  said,  into  the  boiler,  where, 
by  a  new  distillation,  it  is  deprived  of  all  its  remaining  spir- 
ituous portions. 


DISTILLATION.  261 

The  vapor  in  passing  through  the  condensers  gradually 
loses  its  heat,  and  thus  the  water  is  precipitated,  and  the  al- 
cohol being  deprived  of  nearly  all  the  water  which  had  risen 
with  it,  when  it  is  at  length  condensed  in  the  worm,  marks 
the  highest  degree  of  rectification. 

We  see,  from  the  foregoing  statement,  that  by  this  process 
there  can  be  obtained  at  will,  and  by  a  single  operation,  all 
the  degrees  of  rectification  found  in  commerce ;  each  con- 
denser yields  a  different  degree,  and,  by  withdrawing  suc- 
cessively the  product  of  each  one,  we  shall  procure  a  spirit- 
uous liquor,  varying  through  all  the  degrees  from  brandy  to 
the  purest  alcohol.  By  conducting  the  vapors  directly  into 
the  worm,  without  causing  them  to  pass  through  the  inter- 
mediate condensers,  that  degree  which  forms  good  brandy 
of  commerce  is  produced. 

Such  are  the  principles  which  chiefly  constitute  the  pro- 
cess of  Edward  Adam ;  but  independently  of  the  applica- 
tion of  these  principles,  he  has  added  some  improvements  to 
his  apparatus,  which  render  it  more  perfect. 

By  the  aid  of  stop-cocks  and  pipes,  he  directs  the  vapor  at 
pleasure  into  a  small  worm  of  experiment,  there  to  undergo 
condensation,  in  order  that  the  degree  of  rectification  may 
be  judged  of  as  often  as  necessary.  He  also  interposes  a 
worm  between  the  condensers  and  the  worm  which  is  in  the 
water-cask ;  the  upper  worm  is  immersed  in  the  wine,  which 
receives  from  it  a  degree  of  heat  which  hastens  its  ebullition 
when  the  boilers  are  filled.  This  first  worm  so  condenses 
the  alcoholic  vapor,  that  it  flows  liquid  into  the  second  worm, 
and  heats  but  little  the  water  bath  in  which  the  second 
worm  is  immersed. 

From  these  arrangements  there  arise  three  great  advan- 
tages :  in  the  first  place,  the  wine  to  be  distilled  is  heated 
without  material  expense  ;  in  the  second,  the  water  bath  is 
not  obliged  to  be  renewed ;  in  the  third,  the  alcohol  is  al- 
ways obtained  cold,  and  all  danger  of  loss  or  evaporation  is 
avoided. 

M.  Edward  Adam  formed  successively  several  large  es- 
tablishments at  Cette,  Toulon,  Perpignan,  &c.,  and  secured 
a  patent  right  to  insure  the  enjoyment  of  the  advantages 
arising  from  his  inventions  ;  his  success,  however,  very  soon 
awakened  the  attention  of  other  distillers ;  his  results  were 
such,  that  they  could  no  longer  compete  with  him,  and  ac- 
cordingly they  everywhere  made  attempts  either  to  imitate 
or  vary  his  process. 


262  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

The  greatest  number  of  the  attempts  that  were  made  were 
based  upon  the  fundamental  idea,  that  alcoholic  vapor  could 
not  be  condensed  at  so  low  a  temperature  as  steam.  The 
apparatus  of  Edward  Adam  was  immense  and  very  costly  ; 
others  sought  to  reduce  the  dimensions,  and  thus  to  place  it 
within  the  power  of  a  greater  number. 

Isaac  Berard  of  Grand-Gallargues  (department  of  Gard) 
produced,  a  short  time  after,  a  more  simple  apparatus 
than  that  of  Adam,  and  which  obtained  the  preference  over 
his  :  instead  of  covering  the  boiler  with  a  cap,  as  had  been 
formerly  done,  he  surmounted  it  by  a  cylinder,  the  interior 
of  which  was  divided  into  several  compartments  communi- 
cating with  each  other  by  small  openings  :  the  vapor  aris- 
ing from  the  boiling  wine  was  transmitted  into  these  cham- 
bers, where  the  aqueous  particles,  being  condensed,  were 
carried  back  into  the  boiler  by  channels  for  that  purpose, 
whilst  the  alcoholic  vapor  passed  into  a  condensing  cylin- 
der which  was  immersed  in  a  water  bath  :  this  cylinder 
was  divided  transversely,  by  plates  of  copper,  into  four  or 
five  chambers,  communicating  with  each  other  by  open- 
ings, so  that  the  vapor  might  be  made  either  to  pass 
through  all  of  them  before  entering  the  worm,  or  it  might 
be  conducted  thither  after  having  gone  through  two  or 
three.  The  vapor  was  so  far  purified  in  its  passage  through 
these  chambers,  that,  when  at  length  condensed  in  the 
worm,  the  alcohol  marked  from  36°  to  38°,  (:=  specific 
gravity  of  0.847  to  0.842,)  whilst  that  which  was  carried  in- 
to the  worm  without  going  through  the  chambers,  when  con- 
densed, marked  only  from  20°  to  25°,  (=z  sp.  gr.  of  0.935  to 
0.906  :)  all  the  intermediate  degrees  were  obtained  at  pleas- 
ure according  to  tjie  number  of  chambers  through  which  the 
vapor  was  made  to  pass. 

The  apparatus  of  Berard  appeared  so  simple  and  so  ad- 
vantageous, that  it  was  generally  adopted :  Edward  Adam 
attacked  the  author  of  it  as  a  counterfeiter ;  the  expensive 
and  tedious  suits  which  he  was  obliged  to  sustain  against 
Berard  and  many  others,  turned  him  aside  from  his  busi- 
ness, and  this  man,  to  whom  we  owe  nearly  all  the  art  of  dis- 
tilling, died  almost  in  poverty,  a  prey  to  disappointment  and 
chagrin. 

Nearly  at  the  same  period  M.  Cellier,  of  Blumenthal,  con- 
ceived the  happy  idea  of  economizing  time  and  fuel  by 
multiplying  indefinitely  the  surface  of  wine  submitted  to 
distillation  :    to  effect  this,  he  caused  the  vapor  which  es- 


DISTILLATION.  263 

caped  from  the  boiler,  to  circulate  under  numerous  shallow 
vessels  of  copper  placed  one  above  the  other,  and  each  con- 
taining a  portion  of  wine  of  about  an  inch  in  depth.  The 
vessels  were  constantly  supplied  with  cold  wine  which  flow- 
ed from  one  to  the  other,  allowing  the  alcohol  to  evaporate 
from  them ;  the  remainder  flowed  into  the  boiler  to  be  again 
distilled.  The  liquor,  deprived  of  all  its  alcohol,  escaped 
continually  from  the  boiler  by  an  outlet  in  the  side. 

This  process,  improved  by  M.  Derosne,  is  very  expedi- 
tious, and  the  expense  of  fuel  when  compared  with  the  ef- 
fects produced,  is  small. 

This  method  of  distilling  is  called  continual  distillation. 

The  apparatus  of  M.  Cellier,  though  protected  by  a  patent, 
was  imitated,  and  Cellier  experienced  the  same  fate  as  Ed- 
ward Adam,  in  consequence  of  the  suits  he  was  obliged  to 
institute  against  the  counterfeiters  of  his  apparatus :  so  in- 
sufficient is  the  law  regarding  patent  rights. 

Since  that  time  distillatory  apparatus  has  received  an 
almost  endless  variety  of  alterations ;  the  same  general 
principles,  however,  prevail  in  the  construction  of  all  of 
them.* 

Some  have  directed  a  current  of  heat,  proceeding  from  a 
single  fire-place,  under  several  boilers  arranged  side  by 
side  :  others  have  varied  the  number  and  form  of  the  con- 
densers :  several  have  m'^de  arrangements  by  which  the 
filling  of  the  boilers  was  facilitated  ;  for  ascertainng  the 
time  when  the  liquor  no  longer  contained  any  alcohol ; 
for  heating  the  wine  subjected  to  distillation  without  much 
expense;  &c. 

These  successive  discoveries  have  afforded  the  means  of 
distilling,  in  greater  perfection  than  before,  the  mash  of 
grapes,  fermented  grains,  beer,  cider,  &/C. 

By  applying  to  these  fermented  substances  the  simple 
heat  of  aqueous  or  alcoholic  vapor,  the  alcohol  disengaged 
is  of  the  best  kind,  because  the  liquor,  not  being  exposed 
immediately  to  the  action  of  the  fire,  does  not  imbibe  any 
empyreumatic  flavor ;  neither  is  the  boiler  burned  as  it  is 
in  the  distillation  of  the  mash  of  grapes  or  grain  over  the 
naked  fire. 

Being  obliged  either  to  make  choice  amongst  the  kinds 
of  apparatus  in  general  use,  or  to  form   a   new   one  com- 

*  A  work  published  in  two  volumes  by  M.  Lenormand  is  a  complete 
treatise  upon  the  subject,  and  may  be  read  with  advantage. 


264   ^  CHYMISTRY   APPLIED   TO   AGRICULTURE. 

posed  of  all  the  actual  improvements  which  have  been  suc- 
cessively introduced,  I  adopted  the  following. 

A  boiler  capable  of  holding  about  132  gallons  of  wine 
is  placed  over  a  furnace ;  to  the  upper  part  of  the  boiler  is 
affixed  a  pipe,  which  carries  the  vapor  into  a  second  boiler 
containing  106  gallons  of  wine,  in  which  the  pipe  is  im- 
mersed about  six  inches.  With  the  upper  part  of  this 
second  boiler  there  is  connected  a  tube,  which  transmits 
the  vapor  into  a  cylinder  five  feet  in  length  and  fifteen  inches 
in  diameter ;  the  inside  of  this  cylinder  is  divided  into  four 
chambers,  by  plates  of  copper ;  these  chambers  or  cavities 
communicate  with  each  other,  by  small  orifices  in  the  upper 
part  of  the  plates  :  the  cylinder  is  immersed  in  a  trough  of 
cold  water  ;  the  water  of  this  trough  is  renewed  at  the  end 
farthest  from  the  boilers. 

The  vapor  which  is  not  condensed  in  passing  through  the 
chambers  of  the  cylinder,  is  carried  through  a  pipe  into  a 
worm  immersed  in  the  wine,  and  thence  into  a  lower  worm, 
which  is  cooled  in  water.  The  current  of  heat,  after  having 
heated  the  first  boiler,  passes  under  the  second  to  facilitate 
the  ebullition  of  the  liquid. 

Such  is  the  general  arrangement  of  the  apparatus ;  but  in 
order  to  render  the  use  of  it  as  sure  as  it  is  easy,  it  is  neces- 
sary to  enter  into  some  particulars  concerning  its  construc- 
tion. 

1.  In  the  top  of  the  boiler  there  is  a  small  pipe  with  a 
stop-cock ;  upon  turning  the  cock  a  jet  of  vapor  is  thrown 
out,  to  which  a  lighted  taper  is  applied ;  if  the  vapor  takes 
fire,  the  distillation  is  not  completed  ;  if  the  contrary  be  the 
case,  it  is  completed. 

2.  There  is,  at  the  lower  part  of  the  boiler,  a  large  pipe 
with  a  stop-cock  for  drawing  off  the  residuum  or  vinasse. 

3.  A  lateral  stop-cock  for  ascertaining  when  the  boiler  is 
filled  to  a  sufficient  height. 

4.  A  valve,  of  an  inch  and  a  half  in  diameter,  in  the  top 
and  at  some  inches  from  the  place  where  the  boiler  is  con- 
tracted ;  this  is  used  in  cleansing  or  filling  the  boiler. 

At  the  bottom  of  each  chamber  of  the  condensing  cylin- 
der, there  should  be  a  pipe  to  carry  off  the  condensed 
liquid ;  these  pipes  should  communicate  with  a  large  tube 
by  which  the  liquor  will  be  conveyed  into  the  bottom  of 
the  first  boiler;  that  this  may  be  done  with  the  greatest 
ease  and  regularity,  it  is  advisable  that  a  stop-cock  be 
placed  in  each  of  the  pipes  at  the   distance   of  about  an 


DISTILLATION.  265 

inch  from  their  insertion  into  the  common  tube.  As  to  the 
upper  worm,  since  the  wine  which  serves  it  as  a  bath  may 
become  heated  to  a  degree  sufficient  for  producing  alcoholic 
vapor,  it  is  necessary  that  the  cask  in  which  it  is  contained 
should  be  hermetically  closed,  and  that  there  should  be,  in 
the  top,  only  a  socket  to  permit  its  being  filled,  and  a  tube 
by  which  the  alcoholic  vapor  may  be  transmitted  to  the  bot- 
tom of  the  second  boiler.  A  large  stop-cock  placed  lateral- 
ly at  the  bottom  of  the  cask  serves  for  drawing  off  the  hot 
wine  whenever  the  first  boiler  is  to  be  filled. 

The  mechanism  of  this  apparatus  is  easily  understood. 
When  the  two  boilers  and  the  cask  containing  the  worm  are 
filled,  the  liquid  in  the  first  is  heated  to  the  boiling  point ; 
the  second  is  acted  upon  by  the  heat  which  escapes  from  the 
fire  of  the  first.  The  vapors  arising  from  the  first  are  trans- 
mitted to  the  second,  where  they  are  condensed,  and  give 
out  all  their  heat  to  the  body  of  wine  into  which  they  pass. 
This  liquid  is  soon  raised  to  the  boiling  point,  and  all  the  va- 
por arising  from  it  passes  into  the  condensing  cylinder,  the 
coldness  of  which  condenses  the  aqueous  particles,  and  with 
them  a  portion  of  alcohol.  This  condensed  fkiid  is  returned 
by  pipes  into  the  bottom  of  the  first  boiler,  where  it  is  deprived 
of  its  alcohol  by  a  second  distillation.  That  portion  of  va- 
por which  remains  uncondensed,  passes  into  the  first  worm, 
where  it  is  reduced  to  the  liquid  state,  and  this  liquid  upon 
passing  into  the  second  worm  is  deprived  of  all  its  heat.  By 
this  apparatus  excellent  alcohol,  marking  from. 36°  to  38°  of 
the  hydrometer,  (:=  specific  gravity  of  0.847  to  0.837,)  may 
be  obtained  at  a  single  heating. 

As  the  purity  of  the  alcohol  is  increased  by  the  coldness 
of  the  water  in  which  the  condensing  cylinder  is  immersed, 
it  is  necessary  that  this  should  be  changed  as  oft^en  as  pos* 
sible. 

It  is  easily  seen,  that  if  the  tube  which  conveys  the  vapor 
from  the  second  boiler  into  the  condensing  cylinder,  trans- 
mitted it  immediately  into  the  worm,  the  product  would  be 
common  brandy ;  but  as  it  is  freed  from  watery  particles  by 
means  of  the  condenser,  it  yields  a  spirituous  liquor  of  the 
higher  degrees. 

If,  instead  of  filling  the  first  boiler  with  wine,  it  be  filled 
with  water,  and  the  second  with  mash  of  grapes  or  with  fer- 
mented grain,  the  operation  may  be  conducted  in  the  same, 
manner,  and  alcohol  extracted  without  any  hazard  of  burn- 
ing the  boiler. 

23 


266  CHYMISTRY    APPLIED    TO    AGRICtlLTURE. 

This  apparatus  presents  no  danger  of  bursting ;  the  va- 
por has  such  free  issue  from  all  parts,  that  the  compression 
is  never  great  enough  to  occasion  an  explosion ;  it  is  very 
easily  used,  and  may  without  difficulty  be  made  to  under- 
go three  or  four  heatings  every  day,  and  to  furnish  from 
2G4  to  290  gallons  of  good  brandy,  from  wine  yielding  from 

Neither  all  kinds  of  wine,  nor  fermented  liquors  general- 
ly, yield  the  same  quantity  or  quality  of  alcohol :  the  wines 
of  the  south  afford  more  brandy  than  those  of  the  north ; 
fi-om  the  fi-rst  there  may  be  obtained  -^ ;  the  average  is  :^; 
whilst  from  those  of  the  centre  it  is  -i^  and  from  the  north 

from^tOyV 

There  is  great  difference  in  the  strength  of  wines  of  the 
same  country.  Grapes  raised  in  a  light,  dry  soily  and  with 
a  southern  exposure,  yield  wine  highly  cha,rged  with  alco- 
hol, whilst  grapes  of  the  same  kind  growing  in  a  moist  and 
strong  soil,  and  having  a  different  exposure,  furnish  wine 
containing  but  a  small  portion  of  alcohol. 

The  strength  of  wine  depends  upon  the  quantity  of  alco- 
hol contained  in  it,  but  its  quality  and  its  price  cannot  be  cal- 
culated in  the  same  way :  the  odor  and  taste  which  render 
any  kind  of  wine  valuable,  are  qualities  entirely  independent 
o{  the  quantity  of  alcohol  it  contains. 

Wine  rich  in  alcohol  is  strong  and  generous,  but  it  has 
neither  the  mellowness  nor  the  perfume  which  characterize 
some  of  the  other  kinds  of  wine. 

The  brandy  distilled  from  white  wine  has  a  better  taste 
than  that  from  red  wine  :  in  the  south  the  red  wine  is  almost 
everywhere  distilled  j  but  the  brandy  made  there,  though 
very  abundant,  is  less  esteemed  than  that  procured  from  the 
white  wine  of  the  west. 

Wine  which  has  begun  to  turn  sour  furnishes  but  little 
brandy,  and  that  of  a  bad  quality ;  it  is  therefore  necessary 
that  wine  which  is  to  be  distilled  should  have  been  well  fer- 
mented and  kept ;  and  this  explains  the  idea  entertained  by 
many  distillers,  that  wine  should  be  distilled  as  soon  as  it  is 
completely  fermented  :  this  opinion  however  is  unfounded, 
excepting  so  far  as  it  regards  wine  of  an  inferior  quality ; 
strong,  generous  wine,  which  has  been  well  fermented,  and 
well  clarified,  may  be  distilled  at  any  age. 

When  wine  has  been  selected  for  distillation,  the  process 
is  carried  on  in  the  following  manner. 

The  boiler  must,  in  the  first  place,  be  carefully  washed. 


■DISTILLATION,  ^7 

or,  supposing  one  distillation  to  have  been  previously  termi- 
nated, the  stop-cock  must  be  opened  to  allow  the  residuum 
or  vinasse  to  run  out :  through  the  valve  in  the  top  a  stick 
must  be  introduced  v^ith  which  the  liquid  can  be  stirred,  and 
every  thing  removed  which  would  tend  to  form  a  crust  upon 
the  inside  of  the  vessel.  The  stop-cock  may  then  be  closed 
and  water  thrown  into  the  boiler ;  this,  after  being  stirred 
and  allowed  to  remain  some  time,  is  to  be  drawn  oft'  through 
the  stop-cock. 

To  show  the  importance  of  this  preliminary  operation, 
it  is  sufficient  to  observe,  that  if  it  be  neglected,  the  sides 
of  the  boiler  will  become  encrusted  with  tartar  and  lees, 
which  will  speedily  give  to  the  alcohol  a  disagreeable 
flavor ;  and  v/hich  will  likewise  occasion  the  burning  of 
the  copper,  since  it  cannot  be  immediately  moistened  by 
the  liquor. 

As  soon  as  the  boiler  is  thoroughly  <ileansed,  it  may  be 
filled  about  three-fourths  full  of  wine ;  but  before  pouring  the 
wine  in,  the  side  stop-cock  must  be  opened  to  allow  a  passage 
for  the  air  contained  in  the  boiler,  which  would  otherwise 
throw  put  the  wine,  and  likewise  for  ascertaining  wTien  the 
charge  is  complete  <  as  soon  as  there  is  a  suitable  quantity  of 
wine  in  the  boiler,  the  fire  is  kindled. 

The  progress  which  the  vapor  makes  through  the  different 
parts  of  the  apparatus,  is  judged  of  by  the  heat  which  they 
successively  acquire,  as  it  passes  through  them. 

The  first  product  is  alcohol  possessing  neither  an  agreea- 
ble odor  nor  taste,  and  which  is  removed  to  undergo  a  sec- 
ond distillation.  The  alcohol  which  follows  this  is  highly 
concentrated  and  of  a  good  quality :  the  grade  of  it  is  de- 
termined by  the  hydrometer,  and  this  instrument  is  therefore 
placed  at  the  opening  of  the  receiving  vessel,  (bassiot^)  to  in- 
dicate .the  strength  of  the  alcohol  during  the  whole  time  of 
the  operation.  For  some  time  the  hydrometer  indicates 
nearly  the  same  degree ;  but  as  the  heat  of  the  apparatus  and 
baths  increases,  the  aqueous  particles  are  less  perfectly  con- 
densed, and  consequently  the  alcohol,  being  less  concentra- 
ted, is  inferior  in  strength. 

When  the  alcohol  begins  to  fall  below  20°,  (=  sp.  gr.  of 
0.935,)  the  small  stop-cock  in  the  top  of  the  boiler  is  opened 
from  time  to  time,  and  a  lighted  taper  is  presented  to  the  va- 
por issuing  through  it;  when  this  vapor  will  not  take  fire,  the 
operation  is  terminated. 

If  the  same  lowness  of  temperature  could   be  preserved 


268 


CHYMISTRY    APPLIED    TO    AGRICULTURE. 


in  the  water-bath  of  the  condensers,  and  in  the  liquid  in 
which  the  worm  is  immersed,  the  product  of  the,  whole  ope- 
ration would  be  of  the  same  specific  gravity ;  the  degrees 
may  therefore  be  raised  again  when  they  begin  to  sink,  by 
changing  the  baths. 

When  the  operation  is  completed,  the  fire  is  covered,  the 
residuum  of  the  wine  removed,  and  the  boiler  cleansed  and 
again  filled. 

Though  the  alcohol  distilled  in  the  course  of  the  opera- 
tion is  not  all  of  the  same  degree,  it  may  be  made 
so  by  mixing  the  several  portions ;  the  better  way  how- 
ever is  to  redistil  that  which  is  produced  last,  and  thus 
raise  the  whole  to  the  highest  degree  known.  There  is  no 
need  in  any  case  of  having  recourse  to  what  is  called  the 
water-hath. 

Alcohol  should  be  colorless  and  destitute  of  any  un- 
pleasant odor ;  any  bad  qualities  it  may  have,  may  be  re- 
moved by  a  second  distillation  carefully  performed;  in- 
deed it  is  often  enough  to  filtrate  it  through  well  burnt 
charcoal  reduced  to  a  very  fine  powder.  The  bad  quality 
of  alcohol  arises  almost  always  from  want  of  care  in  the 
distillation  of  it,  or  from  a  fault  in  some  one  or  more  of 
the  different  parts  of  the  apparatus  :  sometimes,  however,  it 
happens  that  it  is  owing  to  the  wine's  having  begun  to  turn 
sour. 

As  fast  as  the  vessels  which  receive  the  alcohol  are  full, 
they  are  emptied  into  oaken  casks  set  in  a  cool  place  to  pre- 
vent evaporation :  from  the  casks  the  liquor  acquires  a  yel- 
lowish color,  but  is  unchanged  in  any  other  respect.  Bran- 
dy loses  by  age  the  burnt  taste  which  it  often  has  when  new, 
and  becomes  milder  and  more  agreeable. 

The  instruments  made  use  of  for  ascertaining  the  specific 
gravity  of  alcohol,  do  not  give  it  with  mathematical  precision, 
but  near  enough  for  commercial  purposes :  previous  to  the 
knowledge  of  these  instruments  the  methods  made  use  of 
were  very  inexact. 

The  regulation  of  1729  ordered  powder  to  be  put  into  a 
spoon  and  covered  with  alcohol ;  the  spoon  was  then  placed 
over  the  fire,  and  the  strength  of  the  alcohol  was  judged  of 
by  the  kindling  or  not  kindling  of  the  powder.  To  obtain  by 
this  method  exact  results,  it  was  necessary  that  the  quantity  of 
powder  and  of  alcohol  should  be  always  the  same ;  for  a  larger 
proportion  of  spirit  would  leave,  after  combustion,  a  great- 
er quantity  of  water,  and  this  would  prevent  the  powder  from 
taking  fire. 


BISTILLATION.  369 

The  carbonate  of  potash  has  likewise  been  employed  as  a 
test,  from  its  dissolving  with  more  or  less  ease  according  to 
the  quantity  of  water  contained  in  the  alcohol. 

In  the  year  1770,  the  Spanish  government  ordered  oil  to 
be  made  use  of  as  a  test ;  the  process  consisted  in  letting  a 
drop  of  oil  fall  upon  the  alcohol ;  the  strength  of  the  li- 
quor was  determined  by  the  depth  to  which  the  oil  sunk 
in  it.  It  is  evident  that  this  method  is  very  inexact,  as  the 
depth  to  which  the  oil  will  sink  must  depend  much  upon  the 
size  of  the  drop,  and  the  height  from  which  it  is  allowed  to 
fall. 

In  the  year  1772,  Messrs,  Borie  and  Pouget  arrived  at 
some  conclusions,  which  ended  in  giving  to  commerce  a  hy- 
drometer of  a  sufficient  degree  of  precision  to  prevent  errors 
of  much  consequence  in  estimating  the  specific  gravity  of 
alcohol. 

After  having  made  some  very  exact  experiments  upon  mix- 
tures of  pure  alcohol  with  water,  and  upon  the  effect  of  tem- 
perature at  all  possible  degrees  of  concentration,  these  two 
learned  philosophers  adopted  an  instrument  which  allows  for 
the  variations  of  temperature.  This  hydrometer  has  con- 
tributed not  a  little  towards  raising  the  reputation  of  south- 
ern brandy  in  the  north,  by  furnishing  it  to  commerce  of  its 
full  strength. 

So  necessary  is  the  use  of  a  good  hydrometer  in  commerce, 
that  I  have  seen  for  more  than  five  years  our  Languedoc 
merchants  buying  Spanish  brandy,  of  which  the  strength  was 
not  uniform,  and  confining  themselves  to  rendering  it  of  the 
degree  suitable  for  being  sent  into  the  north,  and  all  the 
other  countries  where  it  is  consumed. 

In  the  south,  where  the  greater  part  of  the  brandy  distrib- 
uted in  commerce  is  manufactured,  it  is  known  under  differ- 
ent names,  which  are  given  to  various  degrees  of  rectifica- 
tion. That  which  marks  from  20°  to  22°  {z=  specific  gravi- 
ty of  0.9a5  to  0.923)  is  called  Holland  proof  . 

This  first  quality,  when  more  concentrated,  and  re- 
duced to  f  by  the  subtraction  of  the  water  contained  in  it, 
takes  the  name  of  three  Jive.  When  deprived  of  |^  or  ^  more 
of  its  aqueous  principle,  it  is  known  as  three  six  and  three 
seven. 

At  Paris,  and  elsewhere,  the  hydrometers  of  Baum6  or 
Cartier  are  employed  for  ascertaining  the  grade  of  alcohol: 
these  instruments  are  less  exact  than  that  of  Borie,  but  are 
sufficiently  so  for  commercial  purposes. 
23* 


270  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

Alcohol  is  used  as  drink  ;  it  is  employed  for  dissolving  re- 
sins, and  it  enters  into  the  composition  of  drying  or  spirit- 
of-ioine  varnishes. 

Alcohol  serves  as  a  vehicle  for  the  aromatic  principle  of 
plants,  and  then  takes  the  name  of  the  spirit  or  essence  of 
such  or  such  a  plant. 

It  is  made  use  of  by  apothecaries  for  dissolving  the  re- 
sinous gums,  and  these  solutions  are  known  by  the  name  of 
tinctures. 

Alcohol  forms  the  basis  of  all  those  drinks  known  by  the 
name  of  liqueurs,  which  are  only  alcohol  sweetened  and  fla- 
vored with  any  aromatic  substances  which  will  give  it  an 
agreeable  taste  and  perfume. 

All  vegetable  substances  which  have  undergone  the  spir- 
ituous fermentation  yield  alcohol  upon  distillation,  but  the 
quantity  and  the  quality  vary  much. 

Alcohol  made  from  cider  has  generally  a  bad  taste,  be- 
cause the  fermented  liquor  contains  much  malic  acid,  a  part 
of  which  rises  with  the  alcohol,  and  remains  mixed  with  it. 

Alcohol  produced  from  the  fermented  liquor  of  wild  cher- 
ries is  stronger  than  that  distilled  from  wine,  and  is  known 
under  the  name  of  kirschwasscr. 

Alcohol  distilled  from  fermented  sirup  of  sugar  is  called 
rum  and  tajia. 

Pallas  saw,  among  the  Kalmucks  and  Tartars,  the  sour 
milk  of  cows  and  mares  distilled :  the  acidification  of  the 
milk  is  facilitated  by  the  addition  of  leaven,  made  of  coarse 
salted  meal,  or  with  rennet  made  of  the  stomachs  of  lambs  : 
the  milk  which  is  destined  to  be  made  into  brandy  is  never 
skimmed.  Distillation  is  performed  in  boilers  covered  over 
with  wooden  caps,  and  the  product  is  received  into  vessels 
which  are  cooled  by  surrounding  them  with  very  cold 
water. 

In  almost  all  known  countries,  brandy  is  distilled  from 
grains,  but  it  is  difficult  to  obtain  it  from  them  free  from 
some  bad  taste  occasioned  by  the  burning  of  the  glutinous 
fermented  matter  which  adheres  to  the  sides  of  the  boiler, 
and  communicates  its  flavor  to  the  liquor  :  this  taste  is  dis- 
guised by  mixing  juniper  berries  with  the  fermented  grain  : 
the  taste  of  the  berries  predominates  in  the  liquor,  and  it  is 
known  under  the  name  of  juniper  brandy  or  gin. 


MEANS   OF   PREPARING   WHOLESOME   DRINKS.  271 


CHAPTER    XVII. 

ON    THE     MEANS     OF     PREPARING     WHOLESOME     DRINKS     FOR 
THE    USE    OF    COUNTRY   PEOPLE. 

A  GREAT  portion  of  the  inhabitants  of  the  country  have 
no  other  drink  than  the  water  furnished  by  wells,  cisterns, 
and  pools. 

The  water  of  wells  varies  much  in  quality,  according  to 
the  nature  of  the  soil  through  which  it  filtrates :  if  that  be 
granitic,  or  formed  by  layers  of  primitive  calcareous  earth, 
the  water  is  excellent ;  when  it  passes  through  beds  of  chalk 
or  gypsum,  it  is  bad  :  in  the  first  case,  the  rain-water  pre- 
serves all  its  purity ;  in  the  second,  it  dissolves,  or  carries 
with  it,  in  a  state  of  extreme  division,  a  portion  either  of  the 
sulphate  or  the  sub-carbonate  of  lime.  Water  of  this 
kind  is  heavy,  very  ill  adapted  to  the  cooking  of  leguminous 
vegetables,  or  to  being  used  in  washing,  as  it  decomposes 
soap,  instead  of  dissolving  it. 

The  best  well-water  is  liable  to  be  rendered  impure  by  the 
filtrations  of  the  juices  from  the  dung  and  firom  the  various 
substances  which  are  decaying  upon  the  surface  of  the  soil 
in  the  vicinity  :  this  evil  is  often  found  to  exist  in  the  coun- 
try, where  wells  and  dung  heaps  are  not  unfrequently  to  be 
seen  in  the  same  enclosure,  and  within  a  short  distance  from 
each  other. 

I  once  knew  the  wells  of  a  whole  village  to  be  rendered 
unwholesome  by  the  rotting  of  hemp  in  the  ditch  which  sep- 
arated the  dwellings  from  the  public  walk.  As  the  state  of 
the  wells  was  attributed  to  some  want  of  care,  I  was  request- 
ed, by  public  authority,  to  ascertain  the  true  cause  of  it,  and 
found  it  to  be  occasioned  by  the  filtration  of  the  water  of  the 
ditch  into  the  wells.  I  caused  the  ditch  and  the  wells  to  be 
thoroughly  drained  three  times,  and  the  water  was  thus  re- 
stored to  purity. 

I  have  often  observed  that  the  use  of  wells  was  necessari- 
ly discontinued  on  account  of  the  proximity  of  a  sheep-fold, 
a  stable,  or  a  ditch  for  manure ;  the  filtrations  from  them 
and  from  the  substances  decomposing  in  their  neighbourhood 
rendering  the  water  totally  unfit  for  use.  To  preserve  the 
water  of  wells  pure,  it  is  therefore  necessary,  that  no  animal 
or  vegetable  substance  which  can  be  decomposed,  be  depos- 
ited near  them. 


272  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

When  the  water  of  wells  is  supplied  by  living  streams,  or 
when  the  ground  around  them  is  paved,  or  consists  of  beds 
of  stone  or  hard  clay  which  will  not  allow  the  water  to  fil- 
trate through,  the  precautions  which  I  have  suggested  are 
not  so  absolutely  necessary  ;  but  these  circumstances  rarely 
occur  in  the  country. 

Cistern-water  would  be  purer  and  more  wholesome  than 
any  other,  if  the  roofs,  eave-troughs,  and  basins,  could  be 
kept  perfectly  clean;  but  the  filth  deposited  by  pigeons 
and  other  birds  upon  the  roofs,  is  carried  by  the  rain  into 
the  reservoir,  and  renders  it  disagreeable  to  drink,  though 
it  is  not  absolutely  unwholesome  :  this  I  have  observed  to 
be  the  case  upon  the  most  elevated  table  lands  of  our  moun- 
tains, where  the  inhabitants  have  no  other  resource  for 
procuring  the  water  necessary  for  domestic  purposes.  I 
have  also  observed,  when  care  was  taken  to  cleanse  the 
troughs  and  reservoirs  frequently,  and  to  conduct  the  first 
portions  of  the  rains  into  pools,  for  the  use  of  the  animals, 
so  as  to  receive  only  that  portion  which  fell  upon  the  roofs, 
after  they  had  been  well  washed,  that  this  water  could  be 
kept  throughout  the  year,  and  that  it  furnished  a  drink 
equally  healthy  and  agreeable. 

In  most  districts,  the  water  of  pools  forms  the  only  re- 
source for  supplying  the  wants,  of  animals ;  and  when  these 
become  dry,  during  the  summer,  the  animals  must  often  be 
driven  a  considerable  distance  to  procure  necessary  drink. 
In  order,  therefore,  to  prevent  the  water  of  pools  from  filtrat- 
ing into  the  ground,  and  likewise  to  preserve  it  sweet,  the 
bottoms  of  pools  should  be  paved. 

In  spite,  however,  of  all  the  precautions  which  can  be 
taken,  it  is  almost  impossible  to  preserve  the  water  in  pools 
from  deterioration  :  the  excrements  of  animals,  and  the 
dirt  from  their  feet,  as  well  as  the  plants  which  always 
spring  up  in  stagnant  water,  very  soon  change  its  color 
and  its  nature;  it  becomes  green  and  thick,  and  to  man, 
disgusting :  fortunately,  animals  are  less  delicate,  and 
can  accommodate  their  inclinations  very  well  to  drink  of 
this  kind:  it  is  even  said,  that  when  accustomed  to  it,  they 
prefer  it  to  the  purest  and  most  limpid  stream.  Such  wa- 
ter rarely  produces  any  bad  effect ;  the  filth  which  is  mixed 
with  it  is  slow  in  decaying,  and  the  plants  which  spring 
up,  contribute  to  its  healthfulness,  and  thus  we  rarely  per- 
ceive from  them  that  fetid  odor  which  indicates  putrefac- 
tion.    The  greatest  fault  in  pond-water,   is  its  temperature 


MEANS    OF    PREPARING   WHOLESOME    DRINKS.  273 

in  summer,  when,  from  the  contact  of  the  atmosphere,  it  be- 
comes too  warm  to  be  an  agreeable  drink. 

It  is  difficult  for  country  people  to  go  out  of  their  accus- 
tomed circle ;  they  employ  themselves  but  little  in  improv- 
ing their  food,  or  drink,  but  take  such  as  nature  yields  ; 
their  drink,  however,  may,  with  but  little  expense,  and 
without  much  care,  be  rendered  more  wholesome  and 
agreeable. 

The  water  made  use  of  is  often  muddy,  or  has  a  bad 
smell,  either  of  which  faults  may  be  corrected,  by  filtering  it 
through  charcoal :  the  process  may  be  performed  in  the  fol- 
lowing manner.  Place  a  large  cask  upright  in  the  coolest 
situation  you  can  command,  knock  out  the  head,  and  form, 
in  the  bottom  of  it,  a  bed  of  clean  sand,  upon  which  place 
one  of  charcoal,  and  above  these,  fasten  securely  a  double 
head  pierced  with  holes ;  when  this  is  done,  the  cask  may  be 
immediately  filled  with  the  water  which  is  to  be  purified  :  the 
filtrated  fluid  may  be  drawn  off  by  means  of  a  stop-cock, 
placed  at  the  bottom  of  the  bed  of  sand :  it  will  be  found 
to  have  become  clear  and  inodorous  in  its  passage  through 
the  sand  and  charcoal.  The  preservation  of  this  apparatus 
requires  but  little  care  :  when  the  charcoal  ceases  to  produce 
the  desired  effect,  it  must  be  either  well  washed  or  replaced 
by  a  new  portion. 

When  a  person  is  laboring  in  the  fields  in  summer, 
the  use  of  warm  water  as  drink,  causes  him  to  perspire 
profusely,  by  which  his  strength  is  reduced.  Cold  water 
might  always  be  procured  by  the  use  of  porous  earthen 
vessels,  the  surfaces  of  which  would  be  constantly  mois- 
tened by  the  transudation  of  the  fluid  through  their  sides : 
the  continual  evaporation  produced  by  the  action  of  the  sun's 
rays  upon  these  vessels,  serves  to  keep  the  water  within 
them  cool.  It  is  by  putting  water  into  their  alcarasas, 
which  they  expose  to  the  sun  and  to  currents  of  air,  that  the 
Spaniards  contrive  to  have  cool  water  even  in  their  hottest 
weather. 

Good  water  is  undoubtedly  the  most  wholesome  drink; 
but  man  has  almost  everywhere  contracted  the  habit  of 
using  fermented  liquors,  and  this  habit  has  created  in  him 
a  want  of  them  ;  so  that  if  he  be  deprived  of  their  use,  he 
loses  his  strength  and  energy,  and  becomes  less  able  to 
work. 

The  best  fermented  drink  is  wine,  but  excepting  in  the 
wine  countries,  where  the  low  price  of  ordinary  wine  ran- 


274  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

ders  the  use  of  it  common,  the  laborer  has  seldom  the  means 
of  procuring  it  daily  :  it  is  therefore  necessary  that  its  place 
should  elsewhere  be  supplied  by  such  other  liquors  as  will 
produce  nearly  the  same  eifect,  and  this  is  done  by  the  fer- 
mentation of  grains,  fruits,  milk,  the  sap  of  trees,  &c.,  from 
the  product  of  which  there  is  formed  in  Europe  a  great  va- 
riety of  liquors ;  some  of  these  have  become  very  important 
articles  of  consumption  and  of  commerce. 

The  peasants  in  the  greater  part  of  our  districts,  have  ac- 
quired the  habit  of  preparing  their  liquors  from  the  fermen- 
tation of  most  of  these  substances ;  and  as  the  only  object  I 
have  in  view  is  to  furnish  information  in  regard  to  extending 
and  perfecting  these  processes,  I  shall  confine  myself  to 
pointing  out  such  methods  as  are  easily  executed,  and  which 
require  the  employment  of  such  substances  only,  as  are 
everywhere  in  the  hands  of  the  agriculturist. 

All  mucilaginous  fruits,  all  fleshy  stone  fruits,  excepting 
those  which  yield  oil,  all  grains  which  contain  gluten,  sugar, 
or  starch,  are  capable  of  undergoing  the  spirituous  or  alco- 
holic fermentation. 

The  expressed  juice  of  saccharine  fruits  may  be  made 
to  ferment  by  exposure  to  a  sufficient  degree  of  heat.  The 
method  most  commonly  pursued,  is  that  of  crushing  or 
grinding  the  fruits,  and  thus  fermenting  the  pulp  with  the 
juice;  in  this  manner  are  treated  apples,  pears,  grapes, 
cherries,  &c.  &c. 

For  such  fruits  as  are  not  very  juicy,  but  contain  how- 
ever some  sugar  and  mucilage,  and  for  such  as  can  be 
made  to  keep  better  by  being  dried,  some  water  is  em- 
ployed to  mix  and  dissolve  the  fermentable  principles  :  in 
this  class  of  fruits  may  be  placed  those  of  the  service-tree, 
the  cornelian  cherry,  the  medlar,  the  mulberry,  the  privet, 
the  juniper,  the  Neapolitan  medlar,  the  thorn-apple,  the 
wild  plum,  &,c.,  and  with  them  the  dried  fruits  of  the  plum 
and  fig-tree,  and  of  some  of  the  other  trees  and  shrubs  be- 
fore mentioned. 

To  produce  the  developement  of  the  saccharine  princi- 
ple in  bread  corns  by  germination,  they  must  be  moistened 
with  water  :  the  spirituous  fermentation  is  afterwards  ex- 
cited in  them  by  immersing  them  in  water,  containing  the 
yeast  of  beer,  or  leaven  made  of  wheat  flour.  The  opera- 
tion of  germination  may  even  be  suppressed  by  mixing 
the  meal  with  a  portion  of  leaven  and  of  luke-warm  water ; 
this  dough  may  be  allowed  to  ferment  for  twenty-four  hours, 


MEANS    OP   PREPARING   WHOLESOME   DRINKS.  275 

and  may  then  be  gradually  diluted  with  water  ;  fermentation 
will  take  place  in  a  few  hours,  and  will  go  on  regularly  dur- 
ing two  or  three  days. 

As  directions  for  the  manufacture  of  cider,  perry,  and 
beer,  for  general  consumption,  are  much  less  necessary  here, 
than  those  for  procuring  for  farmers  wholesome  liquors  at 
a  trifling  expense,  I  shall  confine  my  observations  to  this 
object. 

Grapes  furnish  the  best  liquor,  and  that  in  the  greatest 
quantity ;  but  when  this  is  drunk  clear,  it  serves  but  little 
purpose  for  quenching  thirst ;  when  made  use  of  in  large 
quantities,  it  impairs  the  strength.  The  liquor  called  pi- 
quette,  which  is  manufactured  by  our  farmers,  supplies  ad- 
vantageously the  place  of  wine,  serving  as  a  tonic,  and  at  the 
same  time  quenching  thirst. 

Piquette  is  made  from  the  pressed  and  fermented  mash  of 
red  grapes,  by  means  of  water  filtrated  through  it  till  it  ac- 
quires, in  some  degree,  the  color  and  appearance  of  wine  : 
it  is,  even  in  this  state,  a  better  drink  than  water,  inasmuch 
as  it  is  slightly  tonic ;  its  good  qualities  may  however  be 
much  increased  by  fermentation. 

Piquette  can  be  kept  but  a  short  time  unchanged,  and 
from  this  tendency  to  sour,  it  is  necessary  that  it  should  be 
made  only  in  such  quantities  as  are  immediately  wanted,  and 
that  the  manufacture  of  it  should  be  continued  at  intervals 
throughout  the  year.  For  this  purpose  the  pressed  mash  of 
red  grapes  is  put  into  a  cask,  care  being  taken  to  crowd  it 
in  till  the  cask  is  completely  full,  after  which  it  is  hermeti- 
cally closed  so  as  to  exclude  air  and  moisture,  and  set  in  a 
cool,  dry  place. 

When  the  piquette  is  to  be  prepared  for  use,  the  head  is 
taken  out  of  the  cask,  and  water  is  thrown  upon  the  mash 
till  the  whole  mass  is  moistened  with  it,  and  the  water 
stands  upon  the  top  :  fermentation  soon  takes  place,  as  be- 
comes evident  by  the  light  foam  which  arises ;  it  is  com- 
pleted at  the  end  of  the  fourth  or  fifth  day ;  from  this  time 
the  liquor  may  be  drawn  off  for  daily  use,  the  place  of  the 
portion  removed  being  supplied  by  an  equal  quantity  of  wa- 
ter thrown  in  upon  the  top  of  the  mash.  In  this  manner  a 
cask  of  mash  of  the  capacity  of  66  gallons  may  furnish 
about  4  gallons  of  drink  per  day,  and  will  continue  to  yield 
it  for  about  twenty  days. 

As  the  mash  of  white  grapes  cannot  be  made  to  ferment 
with  the  juice,  this  last  is  separated  and  put  into  casks  to 


5J76  CHYMISTRY   APPLIED   TO    AGRICULTURE. 

ferment  by  itself,  and  the  piquette  is  then  made  by  adding  to 
the  mash  the  necessary  quantity  of  water.  This  liquor  is 
more  spirituous  than  that  made  from  red  grapes,  and  keeps 
better ;  it  is  therefore  reserved  for  use  during  the  latter  part 
of  the  summer. 

If  instead  of  throwing  pure  water  upon  the  mash,  as  is 
everywhere  done,  this  liquid  should  first  be  slightly  sweet- 
ened and  heated,  and  then  receive  the  addition  of  a  little 
yeast,  piquette  of  a  very  superior  quality  would  be  obtained. 
In  the  absence  of  yeast  or  leaven,  the  scum  which  arises 
upon  wine,  especially  white  wine,  during  fermentation,  may 
be  used  for  the  same  purpose  ;  this  foam  or  scum  may  be 
dried,  and  thus  preserved  for  use  without  undergoing  any 
change. 

Well-made  piquette  is  a  very  wholesome  drink  for  country 
people,  from  its  tonic  properties,  as  well  as  its  power  of 
quenching  thirst ;  it  is  far  preferable,  as  a  daily  drink,  to 
wine  :  but  this  resource  is  only  local,  as  in  those  countries 
that  are  most  fruitful  in  grapes,  if  the  harvest  fall  short,  there 
can  be  but  little  piquette  made  ;  it  is  necessary  then  to  be 
able  to  supply  its  place  from  some  other  source,  and  this  is 
done  by  the  fermentation  of  certain  fruits. 

Apples  and  pears,  as  being  the  fruits  that  are  most  abun- 
dantly produced,  are  the  most  valuable  for  the  purpose  of 
manufacturing  liquors:  a  mixture  of  the  two  produces  a 
more  wholesome  article  of  drink  than  does  either  treated 
separately.  The  juice  of  plums  and  of  other  wild  fruits  may 
likewise  be  added,  as  their  astringency  renders  the  liquor  more 
tonic. 

Excellent  liquor  may  generally  be  produced  both  from  ap- 
ples and  pears,  by  following  the  well-known  method  of  mak- 
ing cider,  which  consists  in  grinding  the  fruit  with  a  mill- 
stone and  fermenting  .the  pulp  and  juice  together  :  but  upon 
farms,  where  we  seldom  find  the  means  of  preserving 
liquors  unchanged,  it  is  necessary  that  the  processes  be  sim- 
ple, and  such  as  can  be  made  use  of  for  preparing  them  as 
they  are  needed;  I  shall  therefore  recommend  the  following 
method. 

Begin  to  collect  the  apples  and  pears  which  fall  from  the 
trees  towards  the  end  of  August,  and  continue  to  do  so 
till  they  have  arrived  at  maturity ;  cut  them  in  pieces  as 
fast  as  they  are  gathered,  and  dry  them  first  in  the  sun, 
and  afterwards  in  an  oven  from  which  the  bread  has  been 
drawn.     If  the  fruit  be  well  dried  in  this  manner,  though 


MEANS    OF   PREPARING   WHOLESOME    DRINKS.  277 

it  may  grow  dark-colored,  it  may  be  kept  unchanged  for  sev- 
eral years. 

When  drink  is  to  be  prepared  from  these  dried  fruits,  put 
about  60  pounds  of  them  into  a  cask  which  will  contain  66 
gallons,  fill  the  cask  with  water  and  allow  it  to  remain  four 
or  five  days,  after  which  draw  off  the  fermented  liquor  for 
use. 

The  liquor  thus  procured  is  very  agreeable  to  the  taste  ; 
when  put  into  bottles,  it  ferments  so  as  to  throw  out  the 
corks,  as  frothing  Champagne  wine  does.  Though  whole- 
some and  agreeable,  it  may  become  still  more  conducive 
to  health  by  mixing  with  the  apples  and  pears  ^V  of  the 
dried  berries  of  the  service-tree,  and  ^^^j  of  juniper  berries  ; 
from  these  the  liquor  acquires  a  slightly  bitter  taste,  and 
the  flavor  of  the  juniper  berries,  which  is  very  refreshing, 
and  it  is  besides  rendered  tonic  and  anti-putrescent.  The 
use  of  this  drink  is  one  of  the  surest  means  that  can  be 
taken  by  the  husbandman  for  preserving  himself  from  those 
diseases  to  which  he  is  liable  in  autumn,  and  for  the  attacks 
of  which  he  is  preparing  the  way  during  the  greatest  heats 
of  summer. 

After  the  spirituous  portions  of  the  liquor  have  been 
drawn  off,  very  agreeable  piquette  may  be  made  from  the 
pulp  which  remains  in  the  cask ;  for  this  purpose  it  is  only 
necessary  to  crush  the  fruit,  which  is  already  soft,  and  to  add 
to  it  as  much  luke-warm  water,  to  which  a  small  quantity  of 
yeast  has  been  added,  as  will  fill  the  cask :  fermentation 
commences  in  a  short  time,  and  is  terminated  in  three  or 
four  days.  To  flavor  this  liquor  and  render  it  slightly  tonic, 
there  may  be  added  to  it  before  fermentation,  a  handful  of 
vervain,  three  or  four  pounds  of  elder  berries  and  of  juniper 
berries. 

Cherries,  and  particularly  the  small  bitter  cherries,  when 
ground  and  afterwards  fermented  in  a  cask  in  the  same 
manner  as  the  must  of  grapes,  and  then  pressed  to  sep- 
arate the  juice  from  the^  pulp,  furnish  a  liquor  contain- 
ing much  spirit  The  wine  made  from  cherries,  when  dis- 
tilled, affords  an  excellent  liquor,  which  although  not  ex- 
actly the  same  as  the  good  kirschwasser  of  the  Black  Forest, 
is  yet  a  valuable  drink,  and  is  sold  in  commerce  under  the 
same  name.* 


*  I  know  an  intelligent  landholder,  who,  without  any  interruption 
to  his  other  agricultural  occupations,  makes  every  year  two  or  three 
24 


278  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

The  berries  of  the  service-tree  dried  in  an  oven  and  put 
into  a  cask,  in  the  proportion  of  about  16  or  18  pounds  of 
fruit  to  26^  gallons  of  water,  furnish,  after  four  or  five  days' 
fermentation,  a  very  good  drink.  Plums  and  figs  dried, 
either  by  the  sun  or  in  an  oven,  may  be  made  use  of  for  the 
same  purpose. 

In  order  to  render  the  liquor  more  wholesome  or  more 
agreeable,  several  kinds  may  be  mixed  together,  and  thus 
the  defects  of  one  kind  will  be  compensated  for  by  the  good 
qualities  of  another  :  a  few  handfuls  of  the  red  fruit  of  the 
bird-catcher's  service-tree  counteract  the  flat,  sweetish  taste 
of  certain  other  fruits. 

In  our  farming  districts  the  berries  of  the  juniper  are  care- 
fully collected  and  fermented,  in  the  proportion  of  about  30 
lbs.  of  berries  to  38^  gallons  of  water:  the  drink  procured 
from  these  is  one  of  the  most  wholesome  possible,  but  it  re- 
quires a  little  use  to  reconcile  one  to  the  odor  and  flavor  of 
it ;  those,  however,  who  do  drink  it,  prefer  it,  after  a  short 
time,  to  any  other  liquor.* 

The  use  of  juniper  contributes  so  much  to  health,  that  I 
cannot  too  strongly  recommend  its  being  mixed  in  greater  or 
less  quantities  with  all  fruits  which  are  to  be  subjected  to 
fermentation :  its  flavor  alone  will  disguise  the  taste  of  such 
liquors  as,  without  being  unwholesome,  are  flat,  sickish,  or 
otherwise  unpleasant.  The  rinds  of  oranges  or  lemons,  aro- 
matic plants,  angelica  roots,  peach  leaves,  6lc.  may  likewise 
be  mixed  with  any  of  those  fruits  which  are  naturally  too 
sweet,  and  thus  serve  to  raise  the  flavor  of  the  fermented 
liquor,  and  render  it  more  strengthening  and  efficacious  in 
preventing  the  attack  of  disease. 

That  part  of  CEnologyt  of  which  I  treat  at  this  time,  is 
still  in  its  infancy,  but  I  do  not  doubt  that  by  the  applica- 
tion of  the  true  principles  of  science,  and  by  employing 
only  those  products  which  nature  yields  us  abundantly  and 
without  expense,  we    can  procure   for   the   husbandman  a 

thousand  francs'  worth  of  this  liquor  :  the  peasants  bring  their  cherries 
to  him,  and  he  returns  them  one  half  of  the  product  of  the  distillation. 

*  The  fruit  of  the  strawberry-tree,  medlar,  plum,  Neapolitan  med- 
lar, thorn-apple,  cornelian  cherry,  privet,  &c.  may  be  treated  in  the 
same  manner,  but  the  liquor  made  from  them  is  not  worth  so  much  as 
that  made  from  the  fruits  above  mentioned ;  it  is  used  only  by  the 
poorest  class  of  peasants. 

[t  CEnology,  anologie  French,  from  olrog,  icine,  and  Xoyoq^  account 
cf.    Science  or  knowledge  of  making  wine.  —  Tr.] 


MEANS    OP    PREPARING   WHOLESOME    DRINKS.  279 

variety  of  drinks  more  healthy,  more  agreeable,  and  better 
adapted  for  quenching  thirst,  than  the  weak  and  imperfectly 
fermented  wines  made  from  green  grapes. 

I  have  limited  myself  in  this  work  to  pointing  out  the 
simplest  methods  in  which  such  articles  as  are  within  the 
reach  of  every  peasant  may  be  made  use  of;  if  such 
liquors  as  are  more  spirituous  be  wished  for,  they  can  be 
procured  by  dissolving  from  4  to  6  lbs.  of  the  coarsest  kind 
of  sugar,  in  from  5^  to  10^  gallons  of  warm  water,  and 
throwing  the  solution  upon  the  mash  when  the  cask  is  filled 
with  it.*  To  this  may  be  added  any  number  of  pounds  of 
raisins. 

Liquors  suitable  for  drinking  may  likewise  be  manufac- 
tured from  the  sap  of  several  kinds  of  trees.  In  Germany, 
Holland,  and  some  parts  of  Russia,  as  soon  as  the  returning 
warmth  of  spring  begins  to  cause  the  ascent  of  the  sap,  holes 
two  or  three  inches  deep  are  bored  with  a  gimlet  in  the 
trunks  of  the  birch  trees  ;  through  the  straws  which  are  in- 
troduced into  the  gimlet  holes  there  flows  out  a  clear,  sweet 
juice,  which,  after  having  been  fermented  for  a  few  days,  be- 
comes a  sprightly  liquor,  that  is  drunk  by  the  inhabitants  of 
those  countries  with  much  pleasure ;  it  is  thought  by  them 
to  be  very  serviceable  in  counteracting  affections  of  the  kid- 
neys, stomach,  &c.  A  single  tree  will  furnish  a  quantity  of 
drink  sufficient  to  last  three  or  four  persons  a  week.  The 
natives  of  the  Coromandel  coast  fabricate  their  calou  from 
the  sap  of  the  cocoa-nut  tree.  The  savages  of  America 
prepare  their  chica  from  the  juice  of  the  maize ;  and  the 
drink  of  the  negroes  of  Congo  is  made  from  the  juice  of  the 
palm-tree. 

It  cannot  be  doubted  that  the  sap  of  all  those  trees  which 
afford  a  saccharine  substance  can  be  made  to  yield  a  spirit- 
uous liquor,  but  I  mention  only  these  few  as  instances,  be- 
cause our  own  wants  may  be  abundantly  supplied  from  our 
fruits  and  grains. 

The  fermentation  of  rye  and  barley  has  afforded  from 
time  immemorial  a  liquor,  which  has  supplied  the  place  of 
wine  for  the  use  of  the  common  people  in  nearly  all  those 
countries  in  which  the  vine  cannot  be  made  to  flourish  : 
in  those  where  wine  is  made  abundantly,  the  use  of  beer  ie 
still  very  extensive,  both  on  account  of  the  nutritive  quali- 
ty which  it  possesses  in  a  high  degree,  and  its  power  of 
quenching   thirst.     Though  beer  may  be   brewed  upon  so 

*  Supposing  the  cask  to  contain  66  gallons. 


280  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

small  a  scale  as  to  supply  the  wants  of  a  single  family,  I  shall 
enter  into  no  explanation  of  the  process,  as  it  requires  a  de- 
gree of  care  not  usually  to  be  found  amongst  the  peasantry^ 
and  utensils  which  they  do  not  possess  :  I  shall  confine  my- 
self to  pointing  out  some  processes  by  means  of  which, 
though  they  are  simple  and  imperfect,  some  very  wholesome 
drinks  may  be  obtained  from  grains. 

The  sole  drink  of  the  common  people,  and  one  which  is 
not  disdained  even  by  the  richest  proprietors  throughout 
the  vast  extent  of  the  Russian  territory,  is  quass,  and  it 
is  there  regarded  as  being  nourishing  and  healthy.  We 
are  informed  by  M.  Percy,  Surgeon-General  of  our  armies, 
that  the  French  soldiers  who  had  been  accustomed  to 
drinking  wine  and  beer,  felt  at  first  some  repugnance 
#  towards  the  use  of  quass,  but  they  very  soon  became  ac- 
customed to  it,  and  in  the  end  loved  it  so  much  as  to  man- 
ufacture it  themselves ;  they  found  that  it  gave  them 
strength  and  flesh,  and  preserved  them  from  the  attacks  of 
epidemics. 

In  manufacturing  quass,  one  tenth  part  of  the  rye  to  be 
employed  is  steeped  in  water  till  it  becomes  soft,  it  its  then 
spread  thinly  upon  planks  in  a  place  warm  enough  to  pro- 
duce germination,  and  it  is  there  sprinkled  occasionally  with 
warm  water.  The  remainder  of  the  rye,  after  having  been 
ground,  is  mixed  with  the  germinated  grain,  and  the  whole 
is  diluted  with  two  gallons  and  a  half  of  boiling  water ;  the 
vessel  is  then  set  into  an  oven,  from  which  bread  has  just 
been  drawn,  or  exposed  to  an  equivalent  degree  of  heat» 
during  twenty-four  or  thirty  hours :  if  the  vessel  be  put  into 
an  oven  which  it  is  necessary  to  heat  every  day,  it  may  be 
removed  during  baking,  and  returned  again  after  the  bread 
is  taken  out.  After  this  first  operation  the  fermented  sub- 
stance is  diluted  by  mixing  with  it  2^  gallons  of  water  at  the 
temperature  of  12°  or  15°  ;  *  this  mixture  is  stirred  for  half 
an  hour  and  then  allowed  to  settle. 

As  soon  as  a  deposit  is  formed  and  the  liquor  becomes 
clear,  it  is  thrown  into  a  cask  where  fermentation  takes 
place ;  this  is  completed  in  a  few  days,  when  the  cask  is 
removed  into  a  cellar,  and  the  quass  soon  becomes  clear. 
It  is  in  this  state  that  quass  is  drunk  by  the  Russian  peas- 
ant ;  but  it  is  much  improved  by  being  drawn  off  into  jugs 

[*  No  scale  is  given ;  if  of  the  centigrade,  equal  to  firom  53°  to 59°  ^ 
if  of  Reaumur,  to  from  59°  to  65°.  —  Tr.] 


MEANS    OF   PREPARING    WHOLESOME    DRINKS.  281 

as  soon  as  it  has  formed  its  deposit  in  the  cask,  and  bottled 
after  having  been  preserved  in  these  vessels  till  it  has  become 
cJear. 

Quass  prepared  in  this  manner  has  a  vinous  and  sharp 
flavor  which  is  not  unpleasant.  The  color  of  it  is  not  very 
precise,  being  of  a  yellowish  white. 

The  imperfections  of  quass  might  be  easily  remedied  by 
adding  wild  apples,  or  pears,  or  juniper  berries,  to  the  fer- 
mented substances.  The  fermented  liquor  might  be  racked 
off  several  times  from  its  lees,  and  clarified  by  the  same  pro- 
cess which  we  use  for  wine. 

The  different  deposits  which  are  formed  during  the  manu- 
facture of  quass  are  entirely  of  malt,  and  afford  a  nourish- 
ing and  fattening  food  for  animals. 

I  have  found  that  the  operation  I  have  just  described  for 
procuring  quass,  might  be  simplified  with  the  best  results  by 
putting  the  cask  in  a  place  of  which  the  temperature  was  be- 
tween 18°  and  22°.* 

I  mixed  the  meal  and  malt  with  water  at  the  tempera- 
ture of  25°,  (  =  IT  or  88^°  Fahr.  according  to  the  scale 
used,  —  Tr.)  so  as  to  form  a  porridge;  this  I  put  the  next 
day  into  a  cask,  and  added  water  at  a  temperature  of  20° 
or  22°,  (  =  68°  or  71°  Fahr. ;)  the  liquor  was  stirred  by 
moving  the  cask  as  the  water  was  turned  in,  so  as  to  mix 
its  contents  thoroughly ;  about  one  sixth  of  the  capacity  of 
the  cask  was  left  unoccupied.  The  cask  was  shaken  once 
a  day  for  three  days,  and  afler  that  was  left  undisturbed ; 
at  the  end  of  five  or  six  days  fermentation  was  ended,  and 
nothing  more  remained  to  be  done  than  to  clarify  the 
liquor  according  to  some  of  the  processes  which  I  have  de- 
scribed. 

In  most  of  the  countries  of  the  north,  a  drink,  which  is 
highly  valued  by  the  common  people,  is  prepared  by  sub- 
jecting certain  roots  to  fermentation  in  unheaded  casks, 
into  which  they  are  put,  either  whole  or  cut  into  pieces  ;  the 
most  esteemed  is  procured  from  beet  roots.  These  liquors 
are  nutritive,  wholesome,  and  quenching  to  thirst ;  but 
their  whitish  color  and  acid  taste  will  for  a  long  time  pre- 
vent the  inhabitants  of  our  fields  from  making  use  of  them. 
In  countries  where  wine,  piquctte,  beer,  cider,  &/C.  are 
manufactured  and  sold  at    a   low    price,  it  would   not   be 

[*  No  scale  is  given ;  if  upon  the  centigrade,  between  64.4°  and 
71.8^  J  if  upon  Reaumur's,  between  72i"  and  81i«.  —  Tr.] 
24* 


282  CHYMISTRY   APP1.IED    TO    AGRICULTURE, 

worth  while  to  introduce  the  use  of  a  new  kind  of  drink, 
unless  it  approached,  in  taste,  those  already  in  use,  and 
could  be  made  easily  and  at  a  trifling  expense.  It  is  for 
this  reason  that  I  have  sought  to  improve  the  liquor  which 
is  procured  at  a  low  rate  from  the  various  kinds  of  bread 
corn. 

I  put  into  a  vat  one  hundred  weight  of  rye  or  barley, 
and  pour  upbn  it  a  sufficient  quantity  of  water  to  cover  it 
to  the  depth  of  three  or  four  inches;  after  allowing  it  to  re- 
main four  or  five  liours,  I  stir  it  carefully,  and  by  means  of 
a  shovel  scrape  the  grain  into  that  part  of  the  vat  which  is 
opposite  to  the  opening  formed  in  the  lower  part  and  closed 
with  a  tap.  I  then  draw  out  the  tap,  and  allow  the  water 
to  flow  off;  and  when  the  grain  is  well  drained,  I  close  the 
hole  and  throw  into  the  vat  fresh  water  enough  to  cover 
the  grain ;  after  two  or  three  days  the  grain  becomes  so 
swollen  and  softened,  that  it  can  be  crushed  by  pressing  it 
gently  with  the  thumb  and  finger ;  I  then  draw  off  the 
water,  and  spread  the  wet  grain  upon  the  pavement  or  upon 
planks  to  germinate ;  at  first  it  is  thrown  down  in  a  heap, 
but  when  the  mass  has  become  heated,  which  is  the  case 
in  twenty  or  four-and-twenty  hours,  according  to  the  tem- 
perature, it  is  spread  in  beds  of  two  or  three  inches  in 
thickness. 

Whilst  these  beds  are  heating,  they  must  be  constantly 
stirred ;  and  this  operation  is  repeated  every  six  hours,  and 
oftener  if  heat  is  developed  in  the  mass. 

The  first  appearance  of  the  radicle  is  generally  perceiv- 
ed as  soon  as  the  second  day,  in  the  form  of  a  white  point 
at  one  end  of  the  kernel,  and,  a  short  time  after,  the  plumule 
shows  itself  at  the  other  extremity.  This  is  the  time  for  ar- 
resting germination  ;  and  indeed  it  must  be  done  sooner,  if 
the  radicle  should  become,  as  it  sometimes  does,  more  than 
a  line  or  a  line  and  a  half  in  length,  before  the  appearance 
of  the  plumule. 

The  beds  are  spread  very  thin,  and  often  stirred  with  a 
shovel,  and,  to  destroy  the  germs,  are  formed  either  in  a 
place  exposed  to  the  rays  of  the  sun,  or  in  one  which  is  suf- 
ficiently heated  to  produce  the  same  effect. 

The  malt  thus  prepared  is  thrown  into  a  vat,  and  water, 
heated  to  the  temperature  of  40°,  (  z=  104°  or  112°  Fahr. 
according  to  the  scale  used,  whether  of  the  centigrade  or 
Reaumur.  —  Tr.)  is  gradually  added  to  it,  the  grain  being 
stirred  and  squeezed  by  the  hands,  as  the  water  is  poured 


FARM   BUILDINGS.  23<J 

in.  This  operation  is  continued  till  the  temperature  sinks  to 
25°;  (  =z  either  77°  or  88°  Fahr.  — Tr.)  when  the  malt  is 
converted  into  a  porridge  or  thin  dough  ;  it  is  then  covered 
over  and  allowed  to  remain  half  an  hour.  At  the  end  of 
this  time  boiling  water  is  poured  upon  the  dough,  which  is 
carefully  stirred  till  the  heat  falls  to  50°,  (=  122°  or  144° 
Fahr.)  The  vat  is  now  covered  again  and  kept  for  three  or 
four  hours,  after  which  the  covering  is  removed  and  the  con- 
tents .stirred  till  the  heat  descends  to  20°,  (  =  68°  or  77° 
Fahr.)  when  the  specific  gravity  of  the  liquor  should  equal 
7°  or  8°  of  the  hydrometer. 

In  this  state  a  quantity  of  beer  or  flour  yeast,  proportion- 
ed to  that  of  the  grain  employed,  is  mixed  with  warm  water 
and  turned  into  the  vat,  the  stirring  being  still  continued. 
The  temperature  of  the  place  in  which  fermentation  is  car- 
ried on  should  be  from  GS°  to  77°  Fahr.  Fermentation  will 
be  perceived  in  two  hours  after  the  addition  of  the  leaven, 
and,  if  the  first  operations  have  been  well  conducted,  it  will 
be  terminated  in  two  or  three  days,  when  the  vat  must  be 
covered  over  and  the  liquor  left  to  settle  and  become  clear : 
in  two  days'  time  it  may  be  put  into  a  cask,  and  afterwards 
treated  like  wine. 

This  liquor  is  very  wholesome ;  its  color  is  that  of  opal, 
and  its  taste  slightly  acid.  It  can  be  improved  by  having 
the  mash  of  grapes,  especially  those  of  the  white  kinds,  fer- 
mented in  the  vat  with  the  grain. 


CHAPTER   XVIII. 


OP    FARM  BUILDINGS,  BOTH  FOR  MEN    AND  ANIMALS,  AND  THE 
MEANS    OF   MAKING   THEM    HEALTHY. 

The  situation  of  the  first  habitations  is  determined  by 
the  vicinity  of  a  river,  the  proximity  of  a  fountain,  or  the 
fertility  of  a  spot  of  ground.  The  industry  of  the  inhab- 
itants of  these  dwellings,  and  the  abundant  supply  of  pro- 
visions produced  by  them,  gradually  increase  their  num- 
bers around  the  same  point,  and  the  population  soon 
becomes  divided  into  two  classes,  of  which  one  is  de- 
voted exclusively  to  the  cultivation  of  the  earth,  and  the 


284  CHYMISTRY    APPLIITD    TO    AGRICULTURE. 

Other  is  employed  in  manufacturing  and  furnishing  to  the 
agriculturist  all  the  implements  required  in  labor. 

Rural  buildings  should  be  constructed  without  any  refer- 
ence to  luxury :  the  perfection  of  them  consists  in  furnish- 
ing a  healthful  abode  to  the  people  and  animals  of  the  farm, 
and  in  storing  conveniently  and  safely  the  products  of  the 
various  harvests. 

These  two  requisites  in  farm  building  are  seldom  found 
united :  in  one  place,  men  and  animals  are  crowded  within 
damp  and  badly  ventilated  places,  where  they  contract  innu- 
merable diseases ;  in  another,  the  harvests  are  destitute  of 
any  protection  against  the  ravages  of  animals,  and  the  peas- 
ant sees  the  fruit  of  all  his  labors  devoured  before  his  eyes, 
without  being  able  to  prevent  it. 

I  shall  not  enter  into  particulars  in  regard  to  the  best 
method  of  constructing  farm  buildings  :  others  have  written 
upon  this  subject,  upon  which,  after  all,  it  is  impossible  to  be 
very  precise,  as  the  necessary  arrangements  must  vary  much 
in  different  localities,  according  to  the  kind  of  materials 
that  can  be  procured,  the  kinds  of  animals  with  which  a 
farm  is  stocked,  the  nature  of  the  climate,  the  fortune  of  the 
inhabitants,  dz-c. 

The  art  of  constructing  and  arranging  the  buildings  upon 
a  farm  in  a  convenient  manner  is  not  the  one  upon  which 
rural  proprietors  most  need  instruction ;  but  that  which  re- 
lates to  the  salubrity  of  situation  and  the  means  of  turning 
an  infected  dwelling  into  a  healthful  habitation,  ought  to  find 
a  place  in  this  work  :  to  knowledge  of  this  kind  the  farmer 
is  almost  everywhere  nearly  a  stranger. 

The  choice  of  a  suitable  spot  for  a  farm-house  is  not  so 
easy  a  thing  as  may  at  first  be  thought :  buildings  of  this 
kind  should  always  be  placed  as  nearly  as  possible  in  the 
centre  of  the  domain,  in  order  to  avoid  loss  of  time  and  la- 
bor in  the  transportation  of  the  products  :  the  oversight  of 
a  farm  can  likewise  be  managed  more  easily  by  this  ar- 
rangement. 

Independently  of  these  considerations,  the  buildings  should 
be  situated  upon  the  most  heath ful  part  of  the  farm,  and 
where  the  soil  is  the  least  valuable ;  where  there  is  no  stag- 
nant water,  and  where  there  is  a  plentiful  supply  of  pure  wa- 
ter, both  for  drinking  and  other  domestic  purposes. 

It  is  often  very  difficult  to  find  a  situation  exactly  right 
in  all  these  respects,  but  the  most  important  considera- 
tion, and  the  one  to  which  all  others  should  be  sacrificed, 
is  salubrity. 


FARM    BUILDINGS.  285 

A  farm-house  which  is  built  upon  a  damp  soil,  or  in  a  nar- 
row spot  overlooked  by  surrounding  heights,  is  always  un- 
healthy ;  the  exhalations  which  arise  from  such  spots  become 
stagnant,  and  the  inhabitants  are  continually  surrounded  by 
a  moist  atmosphere  loaded  with  animal  emanations,  and 
with  those  arising  from  all  the  substances  which  are  liable 
to  be  decaying  in  the  neighbourhood  of  a  dwelling.  The 
greater  part  of  the  maladies  with  which  the  inhabitants  of 
the  country  are  afflicted,  are  occasioned  by  the  dampness  of 
their  habitations. 

When,  from  the  nature  of  the  land  and  other  circumstan- 
ces, no  dry  and  airy  spot  can  be  appropriated  for  the  erection 
of  the  necessary  buildings,  the  evil  should  be  lessened  as 
much  as  possible  by  attention  to  certain  precautions  and  ar- 
rangements :  in  all  such  cases  the  house  or  houses  designed 
to  lodge  the  work-people  should  be  built  over  a  cellar,  and 
all  should  be  well  aired  by  means  of  large  doors,  windows, 
and  other  openings.  Nor  are  these  precautions,  though  of 
the  first  consequence,  all  that  is  necessary  ;  there  are  others 
that  it  is  indispensable  to  attend  to  constantly,  in  order  to  se- 
cure health ;  amongst  these  is  the  digging  of  ditches  to  carry 
oflf  stagnant  water  and  dry  the  soil,  and  the  transporting  to 
a  distance  from  the  habitation,  of  all  such  substances  as  are 
susceptible  of  putrefactiori. 

Constant  dampness  in  a  house  is  destructive  not  only  to 
health,  but  to  every  thing  employed  in  a  household,  such  as 
provision,  clothes,  &.c. :  this  cause  alone  is  often  enough  to 
ruin  a  family. 

Those  who  are  so  unfortunate  as  to  be  condemned  to  live 
in  such  places,  should  employ  every  means  in  their  power  to 
counteract  the  evils  arising  from  dampness ;  they  should  not 
remain  long,  either  day  or  night,  in  those  parts  of  a  building 
where  fires  are  not  constantly  made ;  it  would  even  be  use- 
ful to  burn  a  little  straw  occasionally  in  the  middle  of  the  in- 
habited apartments,  as  this  would  serve  to  purify  and  change 
the  air. 

The  greatest  degree  of  cleanliness  should  be  observed  in 
the  interior  of  these  habitations ;  no  substance  which  is  lia- 
ble to  be  decomposed,  should  be  allowed  to  remain  in  them ; 
the  walls,  planks,  and  furniture  should  be  carefully  rubbed 
to  remove  the  dampness  which  they  so  easily  imbibe.  With 
such  precautions  the  unhealthfulness  of  a  house  may  be 
much  lessened. 

The  dwellings  of  animals  become  even  more  easily  in 


286  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

fected  than  those  of  men,  since  no  calculation  is  made  as  to 
the  extent  of  ground,  or  quantity  of  air  that  should  be  allow- 
ed them,  to  admit  of  their  breathing  freely,  and  to  prevent 
their  suffering  from  too  great  an  accumulation  of  heat.  Up- 
on most  of  our  farms  they  are  crowded  into  badly  aired  caves, 
where  their  excrements  are  allowed  to  remain  and  rot 
throughout  the  year,  forming  a  damp  and  hot  atmosphere  ; 
and  from  these  infected  dens  they  are  not  brought  out,  es- 
pecially during  the  winter,  excepting  to  drink.  Is  it  then 
astonishing  that  the  mortality  amongst  the  animals  of  our 
farms  should  be  so  great  ? 

Woolly  animals  do  not  fear  the  cold,  and  the  shelter  of  a 
shed  is  sufficient  for  them  in  winter  :  in  countries  as  cold  as 
France  and  more  damp,  they  are  folded  in  pens  nearly 
through  the  year. 

As  cattle  constitute  the  principal  riches  of  a  farm,  their 
dwellings  should  be  carefully  attended  to :  the  numerous  dis- 
eases which  they  su-ffer  from,  and  especially  those  that  are 
contagious,  and  which  not  unfrequently  destroy  the  whole 
live  stock  of  a  farm,  most  commonly  arise  from  a  neglect  of 
the  cleanliness  necessary  to  health,  in  the  stables  and  sheep- 
folds.  The  emanations  arising  on  all  sides  from  the  bodies  ot 
the  animals,  mix  with  the  putrid  exhalations  arising  from  the 
decomposing  contents  of  their  habitations,  and  the  air  is 
thus  loaded  with  the  elements  of  many  maladies  :  this  state 
of  the  atmosphere  may  be  prevented  by  the  use  of  the  very 
simple  and  efficacious  methods  employed  for  rendering  pris- 
ons and  hospitals  healthful  abodes ;  the  principal  of  these 
are  as  follows. 

That  the  habitations  of  animals  may  be  healthful,  it  is 
necessary  that  they  be  spacious  enough  not  only  to  allow  of 
free  respiration,  but  to  permit  the  inhabitants  to  assume  all 
the  positions  natural  to  them.  It  is  likewise  necessary  that 
they  should  be  well  ventilated ;  this  may  be  done  by  means 
of  windows  or  doors  placed  upon  opposite  sides  so  as  to  form 
a  thorough  draught  of  air  through ;  in  this  way  respirable 
air  will  be  constantly  brought  in,  and  the  pernicious  exhala- 
tions as  constantly  carried  off. 

It  is  likewise  of  great  importance  that  the  floors  of  these 
dwellings  should  be  paved,  and  that  a  slight  slope  should  be 
given  to  them,  by  which  all  liquid  matters  may  be  carried 
off  and  conveyed  into  a  reservoir :  the  pavement  should  be 
raised  a  little  above  the  level  of  the  ground  upon  the  outside 
of  the  buildings. 


FARM    BUILDINGS.  287 

The  cribs  should  be  occasionally  scrubbed  with  weak  lye, 
and  once  a  year  a  coat  of  lime  whitewash  should  be  laid  up- 
on the  walls. 

When  the  floors  of  stables  and  sheep-folds  are  not  paved, 
the  bed  of  earth  of  which  they  are  formed  should  be  remov- 
ed several  times  in  each  year  and  carried  into  the  fields,  its 
f>lace  being  supplied  by  a  bed  of  rubbish  from  salt-petre 
ands,  or  by  any  other  dry  and  porous  substance. 

Those  animals  that  are  accustomed  to  feeding  in  the  open 
fields,  should  not  be  unnecessarily  confined  in  buildings,  as 
they  suffer  from  weariness,  and  from  the  impure  air,  if  de- 
tained too  long  in  them.  There  are  but  few  days  in  the 
year  when  they  may  not  be  allowed  to  come  out  into  the 
open  air  for  several  hours,  since  even  our  greatest  degree  of 
cold  is  not  injurious  to  their  health,  and  as  soon  as  the  build- 
ings are  left  vacant,  the  doors  and  windows  should  all  be 
opened  to  allow  of  free  ventilation. 

In  some  countries  no  use  is  made  of  litter  for  animals, 
and  in  others  the  litter  employed  is  allowed  to  remain  till 
it  is  almost  entirely  decayed ;  both  of  these  methods  are 
wrong  and  contribute  equally  to  render  the  abodes  of  ani- 
mals unwholesome.  The  litter  used  should  be  removed  at 
least  as  often  as  once  a  month ;  and  in  the  intervals  fresh 
layers  should  be  added  as  soon  as  the  others  become  foul 
upon  the  top.  Where  no  litter  is  employed  the  danger  of  in- 
fection must  be  avoided  by  having  the  floors  cleaned  every 
day. 

Another  and  not  less  pernicious  custom  is  that  of  forming 
dung-hills  in  the  corners  of  stables  and  sheep-folds,  instead 
of  removing  the  clearings  to  some  other  place.  By  this 
method  cleanliness  is  secured  to  a  certain  extent,  but  the 
danger  of  infection  is  not  removed. 

When  any  contagious  disease  does  make  its  appearance 
amongst  the  animals  in  the  stables  or  sheep-folds,  the  first 
step  to  be  taken  is  to  separate  the  sick  from  the  well,  in  or- 
der that  they  may  be  subjected  to  different  treatment,  and  to 
remove  the  whole  to  some  other  spot. 

In  order  to  restore  the  infected  building  to  a  state  fit  for 
being  again  inhabited,  proceed  as  follows. 

After  having  removed  all  the  litter,  wash  the  pavement, 
if  there  be  one,  thoroughly ;  if  there  be  none,  scrape  the 
ground  so  as  to  remove  from  it  whatever  may  have  been 
made,  by  moisture,  to  penetrate  into  it.  Burn  sulphur  in 
all  the  different  parts  of  the  enclosure,  so  that  the  vapor 


288  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

may  penetrate  into  every  corner  ;  after  which  whitewash  the 
walls  and  ceilings  with  lime,  and  at  the  end  of  several  days 
the  animals  may  return  without  danger. 

The  vapor  of  chlorine  (oxigenated  muriatic  acid)  may 
be  employed  for  fumigation  instead  of  sulphur,  it  being 
more  active  than  that :  for  this  purpose,  put  into  a  vessel 
which  can  bear  the  fire,  two  ounces  of  finely  pulverized 
oxide  of  manganese,  and  pour  upon  it  ten  ounces  of  the 
muriatic  acid  of  commerce ;  set  the  vessel  over  a  chafing- 
dish  of  burning  charcoal,  and  a  vapor  of  a  greenish  yellow 
color  will  soon  appear  upon  the  surface  of  its  contents. 
This  vapor,  which  is  very  suffocating,  will  spread  through 
the  whole  enclosure  and  destroy  all  infection.  To  make  the 
matter  perfectly  sure,  place  vessels  of  the  same  kind  in  the 
several  parts  of  the  enclosure,  and  thus  kindle  so  many  dis- 
infecting fires. 

Before  the  fumigation  is  begun,  the  outlets  of  the  building 
must  be  carefully  closed,  in  order  that  the  vapor,  by  being 
confined,  may  produce  its  full  effect.  The  persons  having 
the  charge  of  the  heaters  must  go  out  into  the  fresh  air  as 
soon  as  the  vapor  begins  to  affect  their  respiration. 

Animals  that  are  crowded  together  in  low,  damp  places  that 
are  not  well  lighted  and  aired,  often  become  filthy,  and  then 
the  moisture  and  the  animal  exhalations  conspire  to  render 
the  dwelling  an  unwholesome  one.  This  evil  may  be  reme- 
died by  either  of  the  following  methods.  Place  portions  of 
limestone  in  several  vessels  raised  a  little  from  the  ground  ; 
the  limestone  will  absorb  moisture  from  the  atmosphere  and 
likewise  the  carbonic  acid  given  out  by  the  animals,  and  will 
consequently  fall  in  pieces  and  effloresce ;  this  air-slacked 
lime  may  be  used  for  whitewashing  and  other  purposes.  Or, 
kindle  a  strong  flame  with  straw  or  dry  small  wood,  taking 
care  to  watch  it  well,  and  to  remove  the  remains  of  the  fire 
as  it  ceases  to  blaze ;  by  this  last  means  the  whole  internal 
atmosphere  will  be  changed. 

I  have  employed  each  of  these  methods  many  times,  and 
always  with  success. 


WASHING,    BLEACHING,    &/C.  S89 

CHAPTER    XIX, 

ON    WASHING,    BLEACHING,    &C. 

Nothing  is  unimportant  to  the  interests  of  agriculture 
which  tends  to  improve  the  method  according  to  which  the 
daily  work  of  a  farm  is  carried  on  :  this  consideration  has 
induced  me  to  treat  here  of  the  subject  of  bleaching. 

The  object  of  bleaching  is  the  removal  of  spots  and  stains 
from  cloth  :  those  that  most  frequently  occur,  are  occasioned 
by  oil,  grease,  or  perspiration,  and  may  be  removed  by  soap, 
clay,  or  an  alkali :  those  produced  by  the  juices  of  certain 
fruits  require  different  processes. 

Alkalies  can  be  empteyed  in  cleansing  fabrics  of  hemp, 
flax,  or  cotton ;  only  those  of  silk  or  woollen  are  destroyed,  or 
at  least  injured  by  those  substances. 

Before  entering  into  the  details  of  the  bleaching  process, 
I  will  mention  one  common  practice  which  is  very  injurious 
to  cloth. 

When  household  linen  or  articles  of  wearing  apparel  be- 
come soiled,  they  are  usually  thrown  in  a  pile  in  some  cor- 
ner of  the  dwelling,  till  a  sufficient  quantity  is  collected  to 
form  a  washing :  the  consequence  is,  that  the  linen,  being 
impregnated  with  animal  moisture,  even  perhaps  so  as  to  be 
damp,  heats  and  ferments,  and  the  texture  of  it  is  thus  more 
injured  by  lying,  than  by  any  use  which  is  made  of  it  as 
clothing.  To  obviate  this  evil,  soiled  clothing  should  be 
hung  upon  lines  in  a  dry  place,  so  that  the  articles  may  nei- 
ther be  heated  nor  gather  moisture. 

Washing  should  never  be  commenced  excepting  when 
the  weather  is  such  as  to  promise  three  or  four  fine  days. 
Every  housekeeper  knows  by  experience  that  if  she  is  sur- 
prised by  rain  before  her  washing  is  dried,  she  will  lose 
the  greater  part  of  her  labor :  besides,  linen  which  is  put 
away  at  all  damp,  mildews  and  decays,  nor  is  any  thing 
more  injurious  to  health  than  the  use  of  imperfectly  dried 
clothing. 

If  a  bad  state  of  the  weather  should  prevent  the  linen,  &c 
from  being  dried  in  the  open  air,  it  should  be  hung  in  the 
barn  or  around  a  fire  in  the  house,  and  not  be  put  away  in 
closets  and  drawers  till  thoroughly  dry. 

The  first  operation  in   washing   is  that  of   soaking  the 
linen:   for  this  purpose,   the  several  articles   must  be  laid 
25 


290  CHYMISTRY    APPLIED   TO    AGRICULTURE. 

smoothly  in  a  tub,  and  covered  over  with  a  large  coarse 
cloth,  upon  which  water  must  be  poured  till  the  whole  is 
covered  with  it.  The  day  following  a  layer  of  ashes  must 
be  placed  upon  the  coarse  cloth,  so  as  to  be  equally  thick 
over  the  whole  surface.*  The  water  is  drawn  off  from  the 
tub  by  means  of  a  stop-cock  placed  at  the  bottom,  and  is 
thrown  into  a  boiler  under  which  a  fire  is  kindled :  as 
soon  as  the  water  becomes  hot,  it  is  thrown  upon  the  bed 
of  ashes,  and  this  operation  is  repeated  for  some  time;  the 
ley  thus  formed  being  allowed  to  run  out  of  the  tub  to  sup- 
ply the  place,  in  the  boiler,  of  that  which  is  thrown  into 
the  tub. 

In  this  way  the  linen  gradually  becomes  hot  and  the  ley 
acquires  strength :  when  the  liquid  in  the  copper  is  ifear 
boiling,  the  operation  is  discontinue^.  The  linen  is  allowed 
to  remain  in  the  tub  till  the  ley  has  done  running,  after 
which  it  is  carried  to  the  wash-house. 

Nearly  all  fabrics  of  hemp  require  to  be  bleached,  rinsed, 
and  dried,  before  being  used ;  and  as  the  expense  of  the 
soap  required  would  be  considerable,  its  place  may  be  sup- 
plied by  a  soapy  liquor  that  is  much  less  costly :  this  sub- 
stitute is  formed  by  putting  a  quantity  of  such  soda  as  con- 
tains from  ^^jj  to  ^(^  of  pure  alkali,  into  an  earthen  jug, 
with  twenty  times  its  weight  of  water ;  the  jug  must  be 
shaken  occasionally  to  hasten  the  solution,  after  which  it 
will  speedily  become  clear;  this  liquor  has  a  slightly  sa- 
line taste,  and  should  mark  1°  (=  specific  gravity  of  1.007) 
upon  the  hydrometer  of  Baume :  when  it  is  to  be  made 
use  of,  a  quantity  of  olive  oil  t  is  put  into  an  earthen  ves- 
sel, and  from  thirty  to  forty  times  its  weight  of  the  alkaline 
solution  is  poured  upon  it :  by  the  union  of  the  two  fluids 
there  is  immediately  produced  a  white  liquor  of  a  milky 
appearance,  which,  when  shaken,  froths  like  a  solution  of 
soap.  This  liquor  is  put  into  a  bucket  and  diluted  with  a 
little  hot  water,  and  the  linen  is  soaked  in  it,  handled,  rub- 
bed, and  turned,  till  it  is  perfectly  clean.     The  ley  and  oil 

*  In  order  to  render  the  ley  more  active,  a  little  potash  or  soda  is 
generally  added  to  the  ashes  ;  indeed  some  persons  always  mix  a  por- 
tion of  lime  with  them,  but,  unless  great  care  is  used,  the  texture  of 
the  cloth  will  be  injured  by  it. 

t  The  coarsest  kind  of  olive  oils,  such  as  are  known  in  commerce 
under  the  names  of  huiles  de  fabrique,  huiles  de  teintures,  and  huiles 
d'enfer,  are  those  which  should  be  employed  for  this  purpose.  The 
finer  oils  are  not  so  suitable,  as  they  do  not  dissolve  so  well  in  the 
solution  of  soda. 


WASHING,    BLEACHING,    &C.  291 

n«ed  not  be  mixed,  in  any  greater  quantity  than  is  required 
for  use. 

When  I  introduced  in  the  south  the  method  of  whitening 
cotton  yarn  by  the  steam  from  alkaline  solutions,  I  presumed 
that  the  same  might  be  used  advantageously  in  washing  and 
bleaching  household  linen,  and  experiment  has  confirmed  my 
opinion. 

The  apparatus  I  make  use  of  in  this  process,  is  a  boiler  2^ 
feet  across  at  the  opening  and  sixteen  inches  deep,  and  hav- 
ing a  rim  of  1  foot  in  width  around  the  top :  when  the  boil- 
er is  fixed  upon  the  fire-place,  there  is  placed  upon  its  rim, 
and  at  the  distance  of  five  or  six  inches  from  the  opening,  a 
tub  three  feet  in  diameter  and  four  feet  deep,  but  having  no 
bottom ;  the  brick-work  is  raised  all  around  the  tub  a  foot 
from  the  level  of  the  top  of  the  boiler ;  this  brick-work  is 
so  closely  united  to  the  tub,  that  the  steam  can  find  no 
means  of  escaping.  I  have  frames  made  five  inches  less  in 
diameter  than  the  tub,  and  consisting  of  cylindrical  bars  of 
wood  fastened  into  solid  borders  at  top  and  bottom,  so  as  to 
leave  spaces  an  inch  wide  between  the  bars :  the  bars  across 
the  bottom  of  the  frame  should  be  stronger  than  those  of  the 
sides. 

When  this  frame  is  act  into  th«  tub,  there  is  an  interval 
of  two  inches  and  a  half  between  the  two ;  and  the  frame 
rests  equally  upon  the  border  of  the  boiler,  always  leaving 
sufficient  openings  throughwhich  the  steam  can  circulate. 

When  this  apparatus  is  made  use  of,  the  linen  is  soaked 
in  a  tub  containing  a  solution  of  soda  marking  1°  or  2°  on 
the  hydrometer,  (=  specific  gravity  of  1.007  to  1.014;)  it  is 
then  arranged  upon  the  frame,  care  being  taken  to  place 
those  pieces  that  are  most  soiled  at  the  bottom  and  upon  the 
sides. 

Three  or  four  pipes  made  of  white  iron  or  copper,  pierced 
with  small  holes  through  their  length  and  curved  at  the  end, 
are  placed  upon  the  bottom  of  the  frame  at  equal  distances  : 
the  linen  must  be  so  arranged  upon  the  frame,  that  the  pipes 
may  be  put  in  as  far  as  the  top  of  the  curve,  which  ought  not 
to  be  covered  with  the  linen. 

As  soon  as  the  apparatus  is  thus  prepared,  the  remainder 
of  the  ley,  which  has  been  made  to  boil,  may  be  thrown 
over  the  linen ;  the  top  of  the  tub  must  then  be  covered 
over  with  large  coarse  cloths,  with  boards  laid  upon  them. 
.Whilst  these  arrangements  are  in  completion,  the  ley  with 
which  the  linen  is  wetted   drains  off   and    flows    into   the 


292  CHYMISTKY    APPLIED    TO    AGRICULTURE:. 

boiler ;  as  soon  as  it  is  seven  or  eight  inches  in  depth,  the 
fire  may  be  kindled. 

The  steam  arising  from  the  boiling  ley  spreads  itself 
through  the  whole  mass  of  linen,  penetrating  into  all  its  fold- 
ings through  the  openings  in  the  metallic  pipes,  so  that  the 
whole  will  imbibe  a  high  degree  of  heat.  The  boiling  of  the 
ley  may  be  continued  during  three  or  four  hours. 

It  may  be  feared  that  the  bottom  of  the  boiler  may  be 
burned  by  being  kept  dry  from  the  evaporation  of  the  ley ; 
but  there  is  no  danger  of  this,  as  almost  the  whole  of  the 
steam  which  arises  is  condensed  and  returns  again  inta 
the  boiler.  If  it  be  judged  necessary  to  guard  against  the 
possibility  of  this  evil,  a  copper  pipe  of  an  inch  in  diameter 
may  be  attached  to  the  bottom  of  the  boiler,  and  extended 
to  the  outside  of  the  wall  of  the  fire-place,  and  to  this  may 
be  fitted  a  glass  tube,  by  means  of  which  the  height  of  the 
liquor  may  always  be  estimated.  If  by  chance  it  should  hap- 
pen that  the  evaporation  is  not  sufiiciently  compensated  for 
by  the  quantity  of  condensed  fluid  returned,  the  fire  can  be 
checked,  and  a  new  quantity  of  boiling  ley  thrown  into> 
the  tub. 

When  the  heat  has  subsided, — that  is  to  say,  in  eight  of 
ten  hours  after  the  fire  baa  bet;ii  extinguished,- — the  linen  i» 
taken  out  and  carefully  washed. 

In  the  year  1802,  I  had  two  hundred  pair  of  sheets,, 
which  were  taken  from  the  Hotel-Dieu,  washed,  and  was 
assured  by  the  sisters  of  I'Hopital,  that  they  were  cleaner 
and  better  bleached  than  by  the  ordinary  process.  The  ex- 
pense of  the  washing,  of  which  an  exact  account  was  kept, 
was  less  than  three  sevenths  of  the  expense  of  the  common 
method.* 

When  articles  made  of  very  fine  linen  are  to  be  steamed,, 
a  solution  of  soap  should  be  used  in  preference  to  one  of  an 
alkali. 

Cotton  yarn  can  be  bleached  entirely  by  the  above  process. 
If  it  should  happen  that  any  portion  be  less  white  than  the 
rest,  a  few  days'  exposure  in  a  field  will  render  it  perfectly 
white. 

Messrs.  Cadet-de-Vaux  and  Curaudau  have  exerted 
themselves  much  in  improving  this  process,  and  still  more 
in  causing  it  to  be  used,  both  on  account  of  its  simplicity 

*Thi8  apparatus  has  been  established  at  the  Barri^re  des  Bon»^ 
Hommes,  in  the  thread  manufactory  of  the  Messrs.  Bawens.  See* 
the  38th  Vol.  of  the  Jnnales  de  Chimie,  page  291. 


WASHING,    BLEACHING,    &oC.  398 

and  its  economy.  It  is  now  employed  in  many  households, 
and  its  advantages  are  much  extolled. 

The  spots  formed  by  all  substances  upon  clothing,  cannot 
be  removed  by  the  application  of  alkaline  solutions.  In  such 
cases  other  agents  must  be  employed. 

Cloths  of  silk  or  woollen  cannot  be  bleached  in  the 
manner  here  described,  as  the  use  of  the  alkaline  solution 
would  weaken  or  destroy  the  fabric.  It  is  very  imjwrtant 
to  know  the  means  of  removing  spots  and  grease  from 
clothing  of  all  kinds,  and  the  methods  to  be  used  must  de- 
pend upon  the  nature  of  the  cloths  and  of  the  cause  of  the 
stain. 

The  substances  by  which  spots  are  principally  produced 
are  oil,  grease,  wax,  sweat,  ink,  rust,  the  juices  of  red 
fruits,  &;-c.  Scarcely  any  of  these  substances,  when  drop- 
ped upon  clothing,  can  be  removed  by  washing  alone,  even 
in  the  hottest  water;  but  each  one  may  be  dissolved  or 
evaporated  by  certain  agents.  As  I  write  for  the  inhabit- 
ants of  the  fields,  I  shall  speak  only  of  the  simplest  of  these 
agents. 

A  spot  of  wax  may  be  entirely  removed  so  as  to  leave  no 
mark,  merely  by  bringing  a  heated  iron  so  near  it  as  to  cause 
it  to  melt  and  evaporate. 

Spots  produced  by  any  fat  substance  may  be  removed  by 
placing  the  cloth  between  two  pieces  of  soft  brown  paper 
and  applying  a  warm  iron,  such  as  is  used  for  ironing, 
over  the  upper  paper  :  the  oil  is  liquified  and  absorbed  by 
the  paper.  As  the  fixed  oils  are  volatilized  with  more  dif- 
ficulty, the  operation  of  freeing  cloth  from  spots  produced 
by  them,  is  completed  by  the  application  of  such  solvents 
as  are  suited  to  the  purpose.  The  alkalies  hold  the  first 
rank  in  the  class  of  bodies  by  which  the  oils  may  be 
dissolved,  as  they  unite  with  them  and  form  soluble  soaps ; 
but  the  alkalies  act  upon  the  oils  only  when  in  a  nearly 
caustic  state,  and  for  this  reason  the  use  of  them  is  con- 
fined to  a  small  number  of  fabrics,  and  certain  other  sub- 
stances, which,  though  less  active,  will  nevertheless  combine 
with  oil,  are  preferred ;  amongst  these  are  soap,  the  white 
clayey  earths,  the  gall  of  animals,  the  yolks  of  eggs,  ^fcc. ; 
these  last  substances  are  often  mixed  and  formed  into  solid 
bodies  designed  for  the  sole  purpose  of  removing  grease  from 
garments. 

The  volatile  oils  are  likewise  employed  for  the  same 
purpose,  and  they  are  also  used  for  giving  an  agreeable 
25* 


294  emrMisTRY  applied  to  agriculture. 

perfume  to  clothing.  The  vestimental  essences  are  composecJ 
of  these. 

Spots  occasioned  by  the  juice  of  fruit  may,  when  recent^ 
be  effaced  by  washing  in  water ;  but;  when  of  long  standing, 
this  is  insufficient,  and  sulphuric  acid  or  chlorine  (oxygenat- 
ed muriatic  acid)  is  employed.  The  last  of  these  acids  de- 
stroys colors,  and  should  therefore  be  applied  only  to  white 
fabrics  :  it  is  sometimes  combined  with  an  alkali,  that  it  may 
preserve  its  properties  longer ;  in  this  state  it  is  known  by 
the  name  of  Javelte  water.  Sulphuric  acid  acts  much  less 
upon  colors,  and  is  therefore  preferred  for  such  articles  as 
are  dyed  or  printed. 

The  spots  produced  by  the  oxide  of  iron  are  more  lasting 
than  those  occasioned  by  the  oxide  of  any  other  metal.  The 
rust  of  iron,  and  some  of  the  combinations  of  this  metal,  a& 
that  which  exists  in  writing-ink,  when  deposited  upon  cloth, 
become  fixed,  and  form  a  fast  color. 

A  faint  spot  of  iron  rust  may  be  taken  out  by  the  applica- 
tion of  a  weak  acid  ;  spots  of  ink  by  sulphuric  or  muriatic 
acid  much  diluted  ;  but  the  best  method  is  that  of  covering 
the  spot  with  cream  of  tartar  reduced  to  a  fine  powder  and 
then  moistening  it  with  water:  after  having  allowed  the 
cream  of  tartar  to  remain  some  time,  rub  the  cloth  carefully 
and  rinse  it.  When  an  iron-rust  spot  is  of  a  deep  reddish 
yellow  color,  these  acids  are  not  sufficiently  strong,  and  re- 
course must  be  had  to  oxalic,  which  may  be  used  in  the 
Bame  manner  as  the  cream  of  tartar.  The  place  of  oxalic 
acid  may  be  supplied  by  the  salts  of  sorrel  of  commerce ; 
but  the  action  of  the  latter  is  less  perfect. 


CHAPTER    XX, 

ON    THE    CULTIVATION    OF    WO  AD,   AND    THE    EXTRACTION     OF 
INDIGO    FROM    IT. 

For  two  centuries  Woad  (Isatis  tinctaria)  has  been  culti- 
vated in  Europe.  This  plant  is  biennial,  and  its  hairy  and 
branching  stalk  rises  to  the  height  of  three  feet.  As  it  is 
not  killed  by  frost,  it  affords  excellent  food  for  cattle  during 
the  winter.  It  has  however  been  less  cultivated  for  fodder 
tha«  for  yielding  the  only  permanent  blue  color  which  was 
known  before  the  seventeenth  century. 


CULTIVATION    OF    WOAD,    &C.  295 

The  discovery  of  indigo  has  greatly  checked  the  culti- 
vation of  this  plant,  and  it  is  now  limited  to  a  few  localities, 
where  it  is  used  for  forming  that  coloring  preparation  known 
under  the  name  of  coques  de  pastel.  I  am,  however,  much 
inclined  to  think  that  the  cultivation  of  woad  may  be  re- 
stored to  its  former  state,  and  that  it  will  form,  sooner  or 
later,  one  of  the  most  important  branches  of  French  agri- 
culture ;  and  this  opinion  has  determined  me  to  devote  a 
chapter  of  this  work  particularly  to  the  subject,  and  I  shall 
treat  of  it  under  three  heads. 

1st.  The  cultivation  of  Woad. 

2d.  The  manufacture  of  the  cakes  from  the  leaves  of  the 
plant. 

3d.  The  extraction  of  Indigo  from  it. 


ARTICLE   I. 

On  the  Cultivation  of  Woad. 

It  appears  that  the  isatis  tinctoria  may  be  made  to 
flourish  everywhere  excepting  in  moist  lands ;  corn-fields 
and  ground  which  is  prepared  for  cultivation  are  adapted 
to  its  growth  ;  a  good  crop  may  be  procured  upon  alluvial 
soils,  but  strong  soils  are  preferable,  provided  they  are  not 
too  clayey. 

The  ground  in  which  the  seed  of  the  isatis  is  to  be  sown 
must  be  ploughed  three  times,  not  only  that  the  ground 
may  be  thoroughly  softened  and  divided,  but  that  all  the 
weeds  which  would  injure  the  growth  of  the  plant,  and 
increase  the  expense  of  weeding,  may  be  destroyed.  The 
different  ploughings  should  be  performed  at  intervals  of  a 
month  or  three  weeks  from  each  other.  In  strong  lands 
and  those  which  are  disposed  to  retain  too  much  water, 
deeper  furrows  may  be  traced  at  certain  spaces,  so  as  to 
form  small  drains,  by  which  the  water  that  would  injure 
the  plant  is  drawn  off.  The  nature  of  the  manure  which 
is  employed  in  the  culture  of  woad,  exerts  a  powerful  influ- 
ence, not  only  upon  the  vegetation  of  the  plant,  but  upon 
the  quantity  and  quality  of  its  coloring  principle. 

The  manures  which  consist  of  well  decomposed  animal 
or  vegetable  substances  are  the  best,  and  for  this  reason 


296  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

night  soil,  the  dung  of  sheep  and  doves,  the  decayed  frag- 
ments of  wool  and  silk,  and  the  chrysalises  of  the  silk-worm, 
are  preferred  to  any  other  manures. 

Those  substances  that  act  as  stimulants  to  vegetation, 
such  as  lime,  plaster,  marine  salt,  poudrette,  mortar-rub- 
bish, ashes,  &c.  favor  the  growth  of  the  plant  without  affect- 
ing the  coloring  principle. 

When  land  has  been  dressed  with  barn-yard  manure,  it 
may  be  made  to  yield  a  crop  of  grain  or  maize,  and  after- 
wards be  sown  with  woad. 

The  season  for  sowing  the  isatis  varies  much  in  different 
parts  of  Europe.  In  Italy,  Corsica,  Tuscany,  &c.  it  is 
sown  in  the  course  of  the  month  of  November,  As  it  does 
not  receive  injury  from  the  cold,  it  grows  during  the  winter, 
and  in  March  is  sufficiently  strong  to  overcome  the  weeds 
which  usually  make  their  appearance  at  that  season.  From 
the  circumstance  of  its  growing  through  the  winter,  it  may 
be  rendered  a  very  important  article  of  nourishment  for 
horned  cattle. 

In  the  south  of  France,  woad  is  sown  in  March,  and  in 
England  in  February.  In  certain  other  countries  it  is  sown 
after  the  corn  harvests ;  but  in  this  case,  a  season  favorable 
to  vegetation  is  required,  and  the  practice  of  sowing  at  that 
time  can  only  be  followed  advantageously  in  those  climates 
where  rains  are  certain,  so  that  the  cultivator  may  be  able  to 
gather  two  or  three  harvests  of  leaves  before  winter.  His 
fields  of  woad  will  afford  him  pastures  for  his  cattle  during 
the  frosts,  and  he  is  secure  at  the  return  of  summer  of  an 
abundant  harvest  of  leaves. 

The  seed  of  the  isatis  should  be  soaked  in  water  previ- 
ously to  sowing,  as  germination  will  be  hastened  by  it.  The 
seed  is  sown  broadcast,  in  the  same  quantity  as  wheat,  and 
harrowed  in.  The  blade  shows  itself  at  the  end  of  ten  or 
twelve  days.  As  soon  as  the  plants  have  thrown  out  five 
or  six  leaves,  they  must  be  carefully  weeded,  and  this  must 
be  repeated  several  times  before  gathering  the  leaves.  The 
design  of  the  weeding  is  to  remove  all  strange  plants  that 
may  spring  up  in  the  same  soil,  especially  the  roots  of  bas- 
tard woad,  (bourdaigne),  the  mixture  of  which  injures  the 
coloring  matter  of  the  pure  isatis;  and  to  thin  the  rows 
of  stalks,  that  those  remaining  may  have  more  room  to 
grow. 

The  isatis,  like  other  plants,  has  its  diseases  and  its 
enemies.     The   leaves    are    frequently   seen    covered   with 


PREPARATION    OF    WOAD    CAKES.  297 

yellow  spots,  which  turn  brown  and  acquire  the  appear- 
ance of  rust :  this  seems  to  be  occasioned  by  the  sudden 
changes  which  sometimes  occur  in  the  atmosphere ;  the 
rays  of  a  hot  sun  darting  immediately  upon  plants  after  a 
mist  or  rain,  often  produces  a  rustiness  of  the  leaves  and 
stalks. 

It  often  happens,  that,  in  consequence  of  a  great  degree 
of  heat  accompanied  by  drought,  the  plants  are  not  fully 
developed ;  the  leaves  acquire  not  more  than  one  third 
of  their  usual. size,  yet  exhibit  all  the  other  characteristics 
of  perfect  maturity ;  the  harvest  however  is  lost,  for  if  the 
leaves  be  cut  in  that  imperfect  state,  the  plants  either  perish 
or  languish  without  yielding  any  product. 

The  isatis  is  not  exempt  from  the  ravages  of  insects  . 
there  is  one  called  the  flea,  which  often  destroys  the  first 
and  second  harvests  of  leaves;  another,  known  by  the 
name  of  the  louse,  attacks  the  last  leaves,  but  does  less  in- 
jury than  the  other,  because  Uie  first  harvests  are  the  most 
important.  The  snail  and  the  cabbage-worm  likewise  com- 
mit some  depredations  upon  woad. 


ARTICLE   II. 

Preparation  of  Woad  Cakes. 

The  manufacturer  of  woad  cakes  should  avoid  cutting 
the  leaves  of  the  plant,  till  the  period  when  they  are  richest 
in  indigo;  this  substance  is,  to  be  sure,  contained  in  the 
leaves  of  the  isatis,  during  all  the  periods  of  its  vegeta- 
tion ;  but  the  coloring  principle  does  not  present  itself  at 
all  times  in  the  same  quantity  or  of  the  same  quality.  In 
the  young  leaves  the  coloring  principle  is  of  a  delicate 
blue,  in  those  of  a  middle  age  the  color  is  deeper,  and  in 
the  ripe  leaves  it  approaches  to  black.  It  has  likewise 
been  proved  by  observation,  that  the  coloring  principle  is 
obtained  from  the  young  leaves  with  more  difficulty  than  it 
is  from  those  advanced  towards  maturity. 

It  appears,  then,  that  the  most  advantageous  time  for 
gathering  the  leaves  of  woad,  is  when  they  have  acquired 
their  full  growth.  But  by  what  marks  is  this  to  be  deter- 
mined ? 


298  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

The  manufacturers  of  woad  cakes  govern  themselves 
upon  this  subject  according  to  their  own  observations,  and 
their  modes  of  procedure  vary  more  or  less  in  different 
countries. 

In  England  and  Germany,  the  leaves  are  cut  as  soon  as 
they  begin  to  droop,  and  their  bluish  color  to  degenerate 
into  a  pale  green. 

In  Thuringia,  the  leaves  are  gathered  when  they  begin 
to  droop,  and  to  give  out  a  strong,  penetrating  odor. 

In  Tuscany,  the  time  for  cutting  the  leaves  is  judged 
of  by  the  color  which  a  leaf  affords  when  pressed  between 
two  linen  cloths. 

In  the  Roman  states,  the  leaves  are  considered  to  be 
matured  when  they  lose  the  intensity  of  their  color,  and 
begin  to  fade. 

In  Piedmont,  the  leaves  are  gathered  when  they  begin 
to  fall. 

In  the  south,  the  leaves  are  considered  as  being  mature, 
when  they  exhibit  a  violet  shade  upon  their  borders. 

We  are  indebted  to  M.  Giobert,  of  Turin,  for  an  ex- 
cellent treatise  upon  woad,  in  which  he  states  that,  ac- 
cording to  his  observations,  the  quantity  of  indigo  con- 
tained in  the  leaves  of  the  plant  in  the  most  favorable 
seasons,  increases  progressively  from  the  eleventh  to  the 
sixteenth  day  of  their  vegetation,  after  which  time  it  re- 
mains stationary  during  four  or  five  days,  and  then  be- 
gins to  decrease.  The  observations  of  M.  Giobert  have 
been  confirmed  in  the  south  of  France,  at  Bedford,  and  in 
nearly  all  Italy ;  and  from  them  may  therefore  be  deduced 
a  general  rule,  by  which  the  cutting  of  the  leaves  of  woad 
may  be  governed,  whenever  the  vegetation  of  the  plant 
has  been  favored  by  the  combined  action  of  a.  good  soil, 
a  warm  atmosphere,  and  a  suitable  degree  of  moisture  ; 
for  without  this  the  leaves  will  not  have  reached  maturity 
in  twelve  or  sixteen  days,  and  they  should  not  be  gathered 
before  approaching  that  state. 

The  extraction  of  the  indigo  is  uniformly  performed 
with  more  ease  at  an  earlier  period  of  vegetation,  than 
when  the  leaves  are  perfectly  mature ;  the  quantity  of 
coloring  matter  obtained  is  equally  great,  and  the  hue  of 
it  is  handsomer. 

The  leaves  of  the  isatis  are  gathered  by  plucking  them 
off  with  the  hand,  or  by  cutting  the  stalks  with  a  knife 
or  pair  of  scissors ;    but  whichever  way  is  practised,  care 


PREPARATION    OF    WOAD    CAKES.  299 

must  be  taken  not  to  injure  the  stalks  or  tops  of  the  plants  j 
the  cuttings  may  be  repeated  once  in  six  or  eight  days,  so 
as  not  to  allow  time  for  the  quality  of  the  leaves  to  de- 
generate. A  mixture  of  the  leaves  of  strange  plants,  and 
of  the  bastard  woad,  with  those  of  the  isatis  tinctorial  must 
be  carefully  avoided. 

The  leaves,  when  gathered,  are  put  into  baskets  and 
conveyed  to  the  work-shop  in  which  the  manufacture  of 
woad  cakes  is  carried  on ;  when  they  have  begun  to  wither, 
they  are  ground  between  two  mill-stones  equally  chan- 
nelled ;  the  bruised  substance  being  frequently  stirred  with 
a  shovel,  and  the  grinding  continued  till  the  nerves  of  the 
leaves  can  no  longer  be  perceived  by  the  eye.  All  the 
juice  which  flows  out  during  grinding,  is  carefully  pre- 
served to  moisten  the  paste  with  when  it  is  fermenting. 

The  paste  is  carried  under  a  shed,  the  ground  of  which 
is  a  little  sloping,  and  paved  with  cemented  stones,  in 
which  are  little  channels  for  conveying  into  a  reservoir 
the  juice  which  flows  out.  Under  the  highest  part  of  the 
shed  is  formed  a  bed  of  the  paste  three  or  four  feet  in  length ; 
to  render  this  bed  as  compact  as  possible,  it  is  beaten  down 
with  heavy  pieces  of  wood.  Fermentation  commences  in 
a  short  time,  the  mass  swells  and  cracks,  and  there  flows 
out  from  it  a  black  liquor,  which  is  conducted  into  the  res- 
ervoir by  the  channels  in  the  pavement.  In  some  manu- 
factories, this  liquor  is  allowed  to  run  off  upon  the  ground 
without  the  shed ;  but  the  odor  which  it  diff'uses  in  this 
case  is  very  offensive. 

Whilst  fermentation  is  going  on,  attention  is  paid  to  re- 
uniting the  mass  when  it  cracks,  and  to  moistening  it  either 
with  urine,  or  with  the  juice  which  flowed  from  it  when 
between  the  mill-stones. 

After  the  paste  has  fermented  well  for  three  or  four 
days,  the  mass  is  again  beaten  down,  and  this  operation  is 
renewed  several  times  during  the  twenty  or  thirty  days  that 
the  fermentation  lasts ;  the  paste  being  in  the  intervals 
moistened  with  the  juice,  and  the  surface  of  it  united. 

In  a  cold  season,  or  when  the  leaves  are  poor  and  dry, 
fermentation  will  not  be  completed  in  a  month  ;  in  Italy 
they  often  allow  four  months  for  it,  and  sometimes  the  bed 
is  not  removed  till  the  following  spring. 

There  is  a  kind  of  worm  which  often  takes  possession 
of  these  beds,  and  sometimes  in  such  numbers  as  to  de- 
vour all  the  indiffo  contained  in  them ;    in  this  case  the 


300  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

beds  must  be  turned  over,  and,  if  this  be  not  sufficient,  the 
whole  must  be  again  ground  in  the  mill. 

After  fermentation,  the  paste  seldom  appears  of  a  uni- 
form texture,  and  there  will  be  found  in  it  some  remains  of 
nerves  which  are  visible  to  the  eye ;  for  this  reason  it 
is  subjected  to  a  second  grinding,  after  which  it  is  ready 
to  be  made  into  cakes ;  this  is  done  by  filling  round 
wooden  moulds  with  it,  or  by  forming  loaves  four  or  five 
inches  in  diameter,  and  eight  or  ten  in  height,  and  usually 
weighing  about  three  pounds  and  a  quarter.  In  the  south 
of  France  the  moulds  are  usually  much  smaller,  and  the 
loaves  of  woad,  known  by  the  name  of  shells^  weigh  but 
little  more  than  one  pound.  These  cakes  should,  when 
broken,  appear  of  a  violet  color,  and  exhale  a  good  odor. 

The  cakes  are  placed  upon  hurdles,  and  carried  to  a  dry 
and  airy  place  to  harden. 

In  most  countries  the  cakes  are  sold  in  this  state  to  the 
dyers,  who  make  use  of  them  either  to  heighten  their 
woad  dyes,  or  for  dying  by  themselves  a  soft  blue  ;  but  in 
general  they  are  made  to  undergo  another  process,  by 
which  they  are  improved ;  this  is  called  refining.  This 
last  operation  is,  however,  seldom  performed  by  the  manu- 
facturers, but  by  the  dealers  to  whom  they  are  sold  in  large 
quantities  ;  the  reason  of  this  is,  that  the  process  of  refining 
can  be  performed  advantageously  only  on  large  masses, 
and  the  proprietor  of  the  fields  for  cultivating  woad  has 
only  the  product  of  his  harvest,  and  the  conveniences  ne- 
cessary for  making  it  into  cakes. 

For  refining  the  woad  cakes,  it  is  necessary  that  they 
should  either  be  ground  in  a  mill  or  broken  in  pieces  with 
an  axe  ;  the  fragments  are  made  into  beds  about  four  feet 
high,  and  sprinkled  either  with  water,  or,  what  is  prefera- 
ble, with  the  juice  of  the  leaves  ;  heat  is  developed  in  a  short 
time,  and  a  violent  fermentation  takes  place.  At  the  end 
of  six  days,  the  bed  is  turned,  so  as  to  bring  the  interior  or 
under  portion  upon  the  top  ;  this  is  watered  in  the  same 
manner,  and,  five  or  six  days  after,  the  bed  is  again  made 
over  with  the  same  care.  These  operations  are  renewed 
at  short  intervals,  till  the  mass,  having  ceased  to  ferment, 
becomes  cold ;  in  this  state  all  the  animal  and  vegetable 
portions,  with  the  exception  of  the  indigo,  are  decomposed, 
and  it  is  now  sold  to  the  dyers  to  the  greatest  advantage. 

The  mode  of  making  woad  cakes  here  described,  is  un- 
doubtedly the  most  perfect  one,  but  it  is  not  everywhere 


PREPARATION    OF   WOAD    CAKES.  301 

practised.  At  Genoa  they  do  not  refine  them ;  in  the  de- 
partment of  Calvados,  and  upon  the  Rhine,  they  pile  up 
the  leaves  without  grinding  them ;  and  they  mould  the 
cakes  as  soon  as  the  division  of  the  rnass  will  allow  of  this 
operation. 

It  is  necessary  to  observe,  that  an  immense  variety  in 
the  quality  of  the  cakes  is  produced,  not  only  by  the  na- 
ture of  the  soil  and  climate,  but  also  by  the  difference 
of  seasons,  and  by  the  care  bestowed  upon  the  cultivation 
of  the  plant  and  the  gathering  of  the  leaves;  and  from 
these  circumstances  arises  the  different  estimation  in 
which  they  are  held  in  commerce,  and  consequently  the 
various  prices  at  which  they  are  sold.  The  leaves  of 
N^oad  yield  about  ^  their  weight  of  good  cakes;  these, 
when  used  with  indigo  to  form  dyes  for  producing  a 
permanent  blue  color,  serve  not  only  to  facilitate  fermenta- 
tion, but  add  the  indigo  which  they  contain,  to  that  which  is 
brought  from  India,  and  thus  render  the  dye  less  expensive. 

The  cakes,  especially  those  that  have  been  refined, 
contain  alone  a  sufficient  quantity  of  indigo  to  give  to 
cloth  all  the  shades  of  blue,  which  can  be  procured  from 
the  imported  material.  M.  Giobert  states,  that  M.  Alex- 
ander Mazera,  in  the  presence  of  several  skilful  dyers  and 
manufacturers,  and  of  the  commissaries  of  the  Academy 
of  Turin,  colored  with  the  cakes  four  pieces  of  fine  cloth 
of  four  different  shades,  and  they  were  judged  to  be  at 
least  equal  in  brilliancy  and  durability  to  those  obtained 
from  the  best  Bengal  indigo. 

M.  de  Puymaurin  has  published  an  account  of  a  process 
by  which  the  inhabitants  of  the  island  of  Corfu  color,  with 
the  leaves  of  the  isatis,  the  woollen  stuffs  of  which  they 
make  their  clothing.  The  practice  with  them  is  to  cut 
the  leaves  when  the  plant  is  in  flower,  and,  after  carefully 
drawing  out  all  the  nerves,  to  reduce  them  to  paste  in  a 
mortar ;  this  paste  is  dried  in  the  sun,  and  when  it  is  to 
be  used  for  coloring,  is  placed  in  a  bucket  and  moistened 
with  water;  the  mixture  gradually  heats,  and  at  length 
ferments  strongly;  water  and  a  little  weak  ley  of  ashes 
is  added,  and  the  paste  undergoes  the  putrid  fermentation. 
Into  this  composition  the  cloth  which  is  to  be  colored  is 
plunged,  and  allowed  to  remain  eight  days,  turning  it  from 
time  to  time ;  in  this  way  it  acquires  a  deep  and  lasting 
blue.  The  ease  with  which  this  process  is  executed, 
would  render  it  very  useful  in  farmers'  families. 
26 


302  CHTMISTRT    APPLIED    TO    AGRiCTJLTlDRB^ 

ARTICLE  in. 

The  Extraction  of  Indigo  from  Wood. 

Before  the  discovery  of  indigo,  the  isatis  tinctoria  was 
cultivated  for  the  manufacture  of  woad  cakes  in  nearly 
ail  parts  of  Europe :  the  blue  color  obtained  from  this 
plant  was  the  most  durable  one  known,  and  the  commerce 
in  woad  was  immense. 

The  neighbourhood  of  Toulouse,  and  particularly  Lara- 
guais,  furnished  an  enormous  quantity  of  woad,  and  the 
cakes  prepared  there  were  everywhere  considered  of  the 
best  quality :  this  section  of  the  country  became  so  rich, 
that  it  was  called  the  pays  de  cocagne,  from  the  name  of 
its  manufacture ;  and  this  epithet  has  passed  into  a  proverb,, 
and  is  used  to  designate  a  very  rich  and  fertile  country. 

Two  hundred  thousand  packages  of  cakes  were  ex- 
ported every  year  by  the  port  of  Bordeaux  alone :  so  great 
was  the  want  of  this  commodity  amongst  foreign  nations, 
that,  during  the  wars  we  were  obliged  to  sustain,  it  was 
always  agreed  that  the  commerce  in  it  should  be  free  and 
protected,  and  that  foreign  unarmed  vessels  should  be 
allowed  to  come  into  our  ports  to  obtain  it. 

The  finest  establishments  at  Toulouse  have  been  found- 
ed by  the  manufacturers  of  woad  cakes ;  when  Charles  V. 
wished  to  secure  the  ransom  of  Francis  I.,  who  was  a 
prisoner  in  Spain,  he  required  that  the  rich  Beruni,  a 
manufacturer  of  this  article,  should  become  surety  for  it. 

The  indigo,  which  is  an  extract  from  a  plant  of  the 
same  name,  first  made  its  appearance  in  Europe  early  in 
the  seventeenth  century;  and  the  injury  which  the  culti- 
vation of  woad  would  receive  from  it,  was  foreseen  from 
the  first  moment  of  its  introduction.  An  equal  weight 
of  the  pure  coloring  principle  of  indigo  contains  about 
165  times  more  coloring  matter  than  the  woad  cakes  do.  * 
Thus  15  lbs.  of  good  indigo,  such  as  is  usually  employed  in 
dying,  are  equal,  in  point  of  coloring  matter,  to  2625  lbs. 
of  the  woad  cakes.  From  this,  some  judgment  may  be 
formed  of  the  difficulty  of  producing  a  deep  dye  with  the 
woad  alone;   for,  besides  the  inconvenience  of  managing 

*  This  calculation  is  founded  upon  the  supposition  that  100  lbs.  of 
woad  leaves  yield  3  oz.  of  indigo  ;  for  the  cakes,  which  contain  all  the 
ifldigo  of  the  plant,  represent  only  J  of  the  weight  of  leaves  employed 
in  their  manufacture. 


EXTRACTION    OF    INDIGO    FROM    WOAD.  303 

such  an  enormous  mass  of  matter  in  a  dye,  the  colorer 
must  be  very  skilful  in  his  art  to  draw  from  it  a  uniform 
and  well-sustained  color.  It  is  not  then  astonishing,  that 
the  use  of  indigo  should  have  superseded  that  of  the  cakes, 
and  that  consequently  the  culture  of  woad  should  be  much 
diminished. 

Henry  IV.,  who  foresaw  the  depreciation  of  this  princi- 
pal branch  of  French  agriculture,  wished  to  arrest  the 
evil  in  its  infancy,  and  by  an  edict  of  1609,  he  pronounced 
the  penalty  of  death  against  all  those  who  should  make 
use  of  "  the  false  and  pernicious  drug  called  indigo." 
The  same  severity  was  adopted  by  the  governments  of 
Holland,  Germany,  and  England,  though  they  had  not  the 
same  interest  in  the  subject :  the  law  was,  however,  main- 
tained and  executed  only  in  the  last  of  these  kingdoms. 

This  source  of  prosperity  may  easily  be  revived  in 
France,  not  however  by  increasing  the  manufacture  of 
woad  cakes,  of  which  we  cannot  extend  the  use,  but  by 
extracting  from  the  leaves  of  the  woad,  indigo  which  shall 
be  equal  to  that  brought  from  India. 

The  long  war  of  the  revolution  deprived  us  of  naviga- 
tion, and  our  colonial  supplies  of  various  articles  became 
consequently  very  dear  and  incomplete :  in  this  state  of  dis- 
tress and  privation,  government  made  an  appeal  to  our 
learned  men,  upon  the  subject  of  attempting  to  obtain 
from  our  own  soil  a  portion  of  the  supplies,  which  had 
before  been  brought  hither  from  the  New  World.  The 
efforts  made  were  not  unsuccessful,  and  in  a  short  time 
indigo  was  made  from  woad,  which  was  not  excelled  by  the 
best  of  that  brought  from  Guatimala. 

Three  large  establishments  for  the  manufacture  of  thi« 
article,  were  established  at  the  expense  of  government; 
one  at  Albi,  another  in  the  neighbourhood  of  Turin,  and  a 
third  in  Tuscany.  These  establishments  prospered  for 
several  years,  and  the  processes  for  obtaining  indigo  were 
much  improved  in  them  ;  but  the  changes  which  took 
place  in  1813,  deprived  the  manufactories  of  protection  ,* 
the  establishments  were  sold  by  the  respective  govern- 
ments, and  thus  this  profitable  branch  of  industry,  which 
would  have  continued  if  the  establishments  had  belonged 
to  individuals,  has  disappeared.  M.  Roques,  a  skilful 
dyer  at  Albi,  has  alone  maintained  an  establishment  that 
he  had  formed,  and  during  ten  years  he  has  made  use  of 
no  other  indigo  for  coloring  than  that  which  he  prepared 
himself  from  woad. 


304  CHYMISTRY    APPLIED    TO   AGRICULTURE. 

At  this  time,  nothing  more  is  necessary  than  to  make 
known  those  simple  and  advantageous  methods  by  which 
this  branch  of  manufacturing  industry  may  be  conducted. 
I  shall  however  observe,  that  it  is  more  profitable  to  the 
proprietor  to  extract  the  indigo  from  woad,  than  to  convert 
the  leaves  of  the  plant  into  cakes. 

Hellot  assures  us  that  it  had  been  proved  in  his  time, 
that  four  pounds  of  good  Guatimala  indigo  yielded  as  much 
coloring  matter  as  a  package  of  Albigense  woad  cakes 
weighing  two  hundred  and  ten  pounds. 

At  Quiers,  in  Piedmont,  where  the  dyers  are  very  skilful, 
it  is  calculated  that  three  hundred  pounds  of  the  cakes 
afford  as  much  coloring  matter  as  six  pounds  of  the  best 
indigo.* 

According  to  the  experiments  of  M.  Giobert,  there  is  no 
doubt  that  it  is  more  profitable  to  extract  indigo  from  the 
woad  leaves,  than  it  is  to  convert  them  into  cakes. 

The  indigo  which  is  obtained  in  America  from  the  anil^  in 
Indostan  from  the  nuricum^  and  in  Europe  from  the  isatis, 
does  not  differ  sensibly  in  character  :  the  care  which  is 
taken  in  the  manufacturing  of  it,  and  the  state  of  the 
plants,  which  many  circumstances  may  cause  to  vary  dur- 
ing vegetation,  can  alone  produce  some  changes  in  its 
color,  and  cause  its  value  in  commerce  to  vary. 

This  difference  in  the  quality  and  price  of  indigo,  may 
arise  in  some  degree  from  the  different  methods  adopted 
for  extracting  it.  In  America  it  is  made  to  ferment  cold  ; 
in  Java  in  the  form  of  a  decoction ;  and  generally  in  India, 
since  the  discoveries  of  the  learned  Roxburgh,  by  infusion. 

Prior  to  the  year  1810,  a  great  number  of  processes  had 
been  employed  in  France,  Germany,  Italy,  and  England, 
for  obtaining  indigo  from  the  isatis,  without  any  general 
method  having  been  established.  It  was  at  this  period  that 
the  French  government,  urged  by  the  necessity  of  obtaining 
a  coloring  substance  which  the  state  of  the  country  would 
not  allow  them  to  import  but  at  a  great  expense,  formed 
establishments  for  the  extraction  of  indigo  from  woad,  and 
offered  encouragement  to  those  who  would  undertake  the 
business. 

I  shall  not  describe  all  the  methods  that  were  practised 
during  the   three   years    following    1810.     I  shall    confine 

These  results  appear  to  me  exaggerated.  I  place  dependence 
only  on  those  of  the  experiments  which  have  been  made  under  my 
own  inspection. 


EXTRACTION    OF    INDIGO    FROM    WOAD.  305 

myself  to  pointing  out  that  which  is  the  simplest,  least 
expensive,  and  most  expeditious ;  and  which  the  most 
constantly  furnishes  indigo  of  a  uniform  and  good  quality. 

No  other  apparatus  is  required  in  this  process,  than  a 
boiler  for  heating  water,  one  tub  for  leaching,  a  second  for 
a  receiver,  and  a  bucket  in  which  the  water  charged  with 
indigo  is  beaten  to  precipitate  the  fecula. 

The  manner  of  operating,  as  described  by  M.  Giobert, 
author  of  the  process,  is  as  follows. 

Begin  by  heating  the  water  till  it  boils.  In  the  mean 
time,  place  the  leaves  of  woad  (which  have  been  cut 
according  to  the  signs  of  their  fitness  pointed  out  in  the 
process  for  making  woad  cakes)  in  the  tub,  taking  care  to 
arrange  them  so  that  they  shall  not  be  anywhere  crowded, 
and  that  the  distribution  shall  be  equal  throughout  the 
whole  inside  of  the  tub.  Cover  the  tub  with  a  hurdle  of 
osiers,  or  with  a  coarse  net,  and  throw  over  it  a  coarse 
woollen  cloth. 

When  the  apparatus  is  thus  arranged,  pour  boiling  water 
over  the  leaves  till  every  portion  of  them  be  moistened,  and 
the  water  stand  upon  the  top.  Remove  the  woollen  cloth 
and  the  net,  and  stir  the  leaves  gently,  that  the  water  may  be 
equally  diffused  through  them,  and  may  not  descend  to  the 
bottom  of  the  tub,  where  it  will  not  act  upon  them. 

Allow  the  leaves  to  rest  during  five  or  six  minutes,  and 
then  draw  off  the  liquid  through  the  stop-cock  of  the  tub, 
causing  it  to  pass  through  a  sieve  into  the  receiver.  If  the 
color  of  the  liquid  be  too  light,  not  having  the  depth  of 
well-charged  new  white  wine,  the  flow  of  it  must  be 
stopped,  and  that  which  has  run  out  is  to  be  again  turned 
upon  the  leaves,  and  allowed  to  remain  until  it  has  acquired 
the  appearance  just  mentioned. 

As  soon  as  the  liquor  is  drawn  off,  turn  a  fresh  quantity 
of  warm  water  over  the  leaves,  and  allow  it  to  act  upon 
them  for  the  space  of  fifteen  minutes.  During  this  second 
infusion,  remove  the  water  of  the  first  leaching  into  the 
bucket  called  the  beater,  and  cause  that  of  the  second 
leaching  to  flow  into  it,  thus  mixing  the  two. 

As  the  leaves  are  not  by  these  two  leachings  exhausted 
of  all  their  indigo,  cold  water  must  now  be  turned  upon 
them  ;  and  this  may  remain  an  hour  or  two.  The  liquor 
of  this  third  leaching  is  kept  by  itself,  to  be  treated  with 
lime-water.  After  it  has  been  drawn  off,  the  leaves  may 
be  strongly  pressed,  to  obtain  from  them  all  the  juice  whick 
26* 


306  CHYMISTRY    APPLIED    TO   AGRICULTURE. 

may  serve  to  deepen  dyes,  made  of  the  cakes,  for  obtaining 
light  blues.  M.  Pariolati,  dyer  at  Quiers,  has  found  this  an 
excellent  article  for  giving  a  fine  blue  to  silks.  But  it  can  be 
employed  only  when  the  dye-house  is  in  the  neighbourhood 
of  the  indigo  manufactory. 

The  leaves  may  also  be  bruised  after  having  had  the  two 
first  waters  passed  through  them,  and  be  formed  into  cakes 
in  the  usual  manner.  These  cakes  will  not  be  of  the  first 
quality,  but  they  are  useful  as  a  fermentable  substance,  and 
produce  in  this  way  the  same  effect  upon  the  woad  dye 
which  is  prepared  for  coloring.  This  has  been  proved  by 
experiments  conducted  upon  a  large  scale,  and  these  cakes 
are  in  demand  at  a  price  one  third  less  than  those  made 
from  leaves  containing  all  the  indigo. 

The  process  which  I  have  described  for  obtaining  indigo 
by  a  hot  infusion,  is  more  simple  than  any  other  mode. 
But  as  the  indigo  is  more  or  less  formed  or  oxidated  in  the 
leaves,  according  to  the  period  of  their  vegetation,  it  is  not 
at  all  times  equally  soluble,  and  especially  when  it  is  (as  in 
leaves  that  have  passed  their  maturity)  in  the  state  of  black- 
ish blue.  It  is  therefore  necessary,  when  this  process  is  to 
be  followed,  that  the  leaves  should  be  gathered  between  the 
sixteenth  and  eighteenth  day  of  their  growth,  and  before 
their  borders  become  shaded  with  l)lue,  as,  when  that  takes 
place,  the  indigo  has  arrived  at  a  degree  of  oxidation  which 
prevents  it  from  being  completely  dissolved. 

If  the  method  of  obtaining  indigo  by  fermentation  be 
less  advantageous  than  the  one  I  have  already  described, 
it  is  capable  of  beiHg  employed  upon  leaves  which  have 
arrived  at  a  higher  degree  of  maturity,  and  I  shall  therefore 
give  a  short  description  of  it ;  and  I  feel  the  more  inclined 
to  do  this,  because  in  small  manufactories  this  process  is  on 
some  accounts  preferable  to  the  other. 

When  indigo  is  to  be  obtained  by  fermentation,  a  tub  is 
about  three  fourths  filled  with  woad  leaves,  pressed  down 
so  that  they  shall  remain  immersed  in  the  water,  which  is 
thrown  over  them  of  the  temperature  of  15°  or  16°  Reau- 
mur, {=:  65°  to  68°  Fahr.)  The  heat  of  the  manufactory 
should  be  at  the  same  degree.  Fermentation  will  in  a 
short  time  be  evident  by  the  appearance  of  bubbles,  which 
rise  and  break  upon  the  surface.  This  should  be  termi- 
nated in  eighteen  hours.  The  period  when  it  should  be 
stopped,  may  be  known  by  the  color  of  the  water  being 
that  of  a  yellow  lime,  and  by  the  formation,  upon  the  top,  of 


EXTRACTION   OP    INDIGO    FROM   WOAD,  307 

a  thin,  greenish,  and  iridescent  pellicle.  When  in  this 
state,  the  liquor  is  to  be  drawn  off  into  the  receiving  tub, 
and  changed  from  that  into  the  beating-vessel. 

In  both  methods,  it  is  necessary  to  precipitate  the  indigo 
virhich  is  held  in  solution  or  in  suspension  in  the  water ; 
and  this  operation,  which  is  called  beetling  or  beating,  is 
needed  to  give  to  the  indigo  the  blue  color  which  belongs 
to  it. 

There  are  two  methods  of  beating  which  are  practised, 
one  being  applicable  to  the  liquor  obtained  by  infusion, 
and  the  other  to  that  procured  by  fermentation.  I  shall 
here  describe  both  of  them. 

As  soon  as  the  heat  of  the  liquor,  which  has  been  passed 
through  the  leaves  in  the  manner  described  in  the  first 
process,  has  fallen  to  between  120°  and  111°  Fahrenheit, 
beating  is  commenced.  The  instrument  employed  for  this 
purpose  is  a  broom,  or  a  handful  of  willow  twigs  from  which 
the  bark  has  been  peeled.  With  this  the  liquor  is  forcibly 
agitated,  the  quickness  of  the  motion  being  gradually 
lessened  as  the  infusion  cools. 

As  soon  as  a  white  foam  rises  upon  the  top,  beating  is 
suspended,  but  is  resumed  again  as  soon  as  the  foam  sub- 
sides, and  assumes  a  fine  blue  color.  If  the  liquor  is  too  hot, 
or  has  been  too  much  beaten,  the  blue  borders  upon  the 
violet ;  otherwise  it  is  the  color  of  the  sky.  Beating  is 
continued  at  intervals,  allowing  the  foam  to  exhibit  its 
color.  When  by  rest  it  appears  only  of  a  pale  blue,  the 
beating  is  continued  without  any  interruption.  When  the 
foam  remains  white,  or  changes  to  a  reddish  color,  the 
operation  draws  to  a  close. 

By  beating,  the  color  of  the  water,  which  was  that  of 
white  wine,  becomes  more  and  more  brown.  The  beating 
is  ended,  when  upon  pouring  the  liquor  into  a  glass  vessel,  it 
appears  of  a  uniform  brown.  Should  a  tinge  of  bluish  green 
be  perceived  near  the  sides  of  the  glass,  the  beating  must  be 
continued.  Upon  the  whole,  it  is  better  to  beat  it  too  much 
than  too  little.  The  time  requisite  for  performing  the 
operation  upon  the  liquor  drawn  from  three  hundred  pounds 
of  leaves,  is  generally  about  an  hour  and  a  half. 

When  the  liquor  is  at  length  left  undisturbed,  the  indigo 
is  deposited  in  grains  at  the  bottom  of  the  bucket.  Eight 
or  ten  hours  are  sufficient  for  this  purpose.  The  liquor  is 
then  to  be  drawn  off"  and  the  indigo  dried,  in  order  that  all 
the  water  which  could  cause  it  to  ferment  may  be  separat- 
ed from  it. 


308  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

In  this  operation,  no  foreign  substance  by  which  the 
indigo  can  be  adulterated  is  employed  ;  and  it  is  therefore 
obtained  as  pure  as  the  best  of  the  imported  kind. 

When  the  leaves  of  the  isatis  are  operated  upon  with 
cold  water  by  maceration,  fermentation,  or  any  other 
method,  the  indigo  cannot  possibly  be  separated  by  beating. 
The  reason  of  this  is,  that  the  elevation  of  the  tempe- 
rature is  not  high  enough  to  cause  the  combination  of 
oxygen  with  the  indigo,  and  thus  to  give  it  the  color  and 
other  characteristics  which  render  it  so  valuable  in  the  art 
of  dyeing. 

The  substance  which  in  these  cases  is  most  usually 
employed  to  produce  precipitation,  is  lime-water;  but  as 
this  process  requires  much  attention,  I  shall  describe  par- 
ticularly the  use  and  action  of  this  ingredient,  that  the  man- 
ufacturer may  be  the  better  able  to  direct  it. 

After  all  the  water  which  has  been  prepared  in  the  course 
of  the  day,  has  been  collected  in  a  tub,  the  operation  of 
precipitating  the  indigo  from  it  is  commenced  in  the  fol- 
lowing manner. 

The  liquor  is  beaten  almost  uninterruptedly,  and  without 
any  particular  method,  for  half  an  hour,  the  operation  being 
interrupted  only  to  allow  the  foam  to  subside  and  exhibit 
its  color.  When  the  liquor  begins  to  appear  of  a  deep 
brown,  five  or  six  pints  of  lime-water  are  thrown  into  it. 
The  beating  is  continued,  and  the  lime-water  added  at  inter- 
vals, till  the  liquor  exhibits  a  greenish  yellow,  begins  to  grow 
turbid,  and  to  show  in  a  state  of  suspension  the  substance 
which  is  about  to  be  precipitated.  The  quantity  of  lime- 
water  which  is  necessary  to  be  used  in  this  process,  when 
added  at  intervals,  in  the  manner  here  directed,  is  never 
more  than  one  tenth  of  the  volume  of  the  liquor  with  which 
it  is  mixed ;  but  if  the  lime-water  be  all  thrown  in  at  once, 
the  lime  more  than  saturates  the  carbonic  acid  of  the  liquor, 
and  the  carbonate  thus  formed,  being  precipitated,  mixes 
with  and  weakens  the  indigo. 

In  the  last  described  method  of  producing  precipitation, 
a  large  quantity  of  air  is  introduced  into  the  liquor  by 
beating.  This  combines  with  th^  indigo,  rendering  it 
insoluble  in  water,  and  forming  at  the  same  time  a  great 
deal  of  carbonic  acid.  The  admixture  of  a  small  quantity 
of  lime-water  after  each  beating,  produces  an  acidulated 
carbonate,  which  remains  in  solution  in  the  liquor,  and  a 
kind  of  soapy  combination  with  the  extractive  and  vegeto- 


EXTRACTION    OP    INDIGO    FROM    WOAD.  309 

animal  portions  of  the  plant,  so  that  the  indigo  disengaged 
from  its  several  combinations  can  be  oxidated  and  precipi- 
tated more  easily,  and  in  a  state  of  greater  purity. 

The  first  result  of  this  process  appears  to  be  a  much 
smaller  quantity  of  indigo  than  is  obtained  by  employing  a 
volume  of  lime-water  equal  to  that  of  the  liquor.  But  the 
indigo  obtained  is  purer,  being  equal  in  quality  to  the  kind 
which  bears  the  highest  price  in  commerce.  This  process 
may  be  employed  in  all  cases ;  even  when  the  infusion  of 
leaves  is  at  122°  Pahr.  The  length  of  time  during  which 
beating  must  be  continued  in  those  cases  in  which  it  can 
alone  be  employed,  is  much  diminished  ;  and  yet  the  indigo 
obtained  is  equally  as  pure. 

When  all  the  indigo  has  been  precipitated,  the  water  is 
drawn  off.  The  precipitated  fecula  requires  some  further 
operations  to  bring  it  to  the  requisite  degree  of  perfection. 

The  precipitated  indigo  still  contains  a  greater  or  less 
portion  of  particles  which  are  not  sufficiently  oxidated,  and 
consequently  it  has  neither  the  color  nor  properties  which 
characterize  gpod  indigo.  Prolonged  beating  would,  it  is 
true,  bring  these  portions  to  the  desired  state  ;  but  it  would 
likewise  cause  those  particles  which  had  been  first  oxida- 
ted to  imbibe  an  additional  quantity  of  oxygen,  by  which 
their  color  would  be  too  much  deepened,  and  indigo  of 
this  quality  would  be  rejected  in  commerce  as  burnt ;  it 
is  therefore  better  to  give  to  the  imperfectly  oxidated 
particles  the  degree  of  oxidation  required,  in  the  following 
manner. 

Stir  the  liquid  fecula  strongly,  and  throw  over  the  whole 
mass  a  volume  of  warm  water,  double  that  of  the  fecula  ;  by 
this  means  the  perfect  indigo  will  be  precipitated,  and  the 
other  will  be  held  in  suspension  by  the  water.  This  water 
is  to  be  drawn  off  and  treated  with  lime-water,  by  which 
the  green  color  becomes  of  a  yellow  brown,  and  the  indigo 
being  rendered  insoluble  is  precipitated. 

It  sometimes  happens,  that  the  liquor  which  has  been 
treated  with  lime-water,  and  beaten,  if  the  operations  have 
not  been  well  conducted,  still  retains  a  portion  of  indigo 
in  solution ;  this  can  be  ascertained  by  adding  lime-water 
to  a  small  portion  of  it,  to  see  if  it  will  become  brown. 

That  indigo  may  have  the  purity  and  brilliancy  belonging 
to  it,  it  must  be  twice  washed,  once  in  cold,  and  once  in 
hot  water. 

To  perform  the  first  washing,  collect  all  the  fecula  in  an 


310  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

earthen  pan,  and  pour  over  it  four  or  five  times  its  own 
volume  of  very  pure  water ;  stir  the  fecula  very  carefully, 
raising  it  with  the  hand  in.  the  water,  and  let  this  be  re- 
peated occasionally  for  several  hours,  after  which  it  may  be 
allowed  to  settle;  when  the  fecula  is  entirely  deposited, 
turn  off  the  water  and  add  more,  and  let  this  be  repeated 
till  the  water  is  no  longer  colored.  As  washing  in  cold 
water  will  not  remove  all  the  foreign  substances  which  in- 
jure indigo,  it  is  necessary  to  have  recourse  to  hot  water  ; 
but  to  perform  the  last  washing  economically,  it  is  necessary 
to  collect  the  product  of  several  cold  washings,  and  to 
operate  upon  large  quantities. 

Before  commencing  the  washing  in  hot  water,  the  fecula 
receives  a  certain  degree  of  consistency  by  compression, 
after  which  it  is  placed  in  a  tub  and  allowed  to  ferment 
during  ten  or  twelve  days,  till  it  exhales  a  strongly  acid 
odor ;  by  this  means  a  mealy  portion,  which  escapes  the 
action  of  cold  water,  is  decomposed.  The  process  of  wash- 
ing in  hot  water  is  next  performed  in  the  same  manner  as 
I  have  directed  for  the  cold  washing ;  the  operation  may, 
however,  be  shortened,  and  very  nearly  the  same  results 
obtained  by  boiling  the  indigo  in  water,  taking  care  to  stir 
it  the  whole  time. 

To  bring  indigo  to  the  greatest  degree  of  purity,  and  to 
give  it  the  forms  which  it  ought  to  have  in  commerce,  it 
must  undergo  certain  other  processes. 

The  washings  in  water  remove  all  those  substances  which 
are  capable  of  being  dissolved;  fermentation  decomposes 
certain  principles  which  are  foreign  to  the  nature  of  indigo ; 
but  there  still  remain  in  it,  in  greater  or  less  quantities, 
certain  earths,  which,  according  to  their  several  proportions, 
adulterate  it,  and  which  should  therefore  be  extracted;  for 
this  purpose  the  indigo-paste  is  thrown  into  a  vat  furnished 
with  two  or  three  stop-cocks  situated  at  various  heights,  and 
is  there  diluted  with  a  large  quantity  of  water.  The  indigo 
is  carefully  mixed  with  the  water,  so  that  all  the  particles 
of  it  may  swim  separately  in  the  liquid  ;  the  upper  stop-cock 
is  then  opened  and  the  water  drawn  off  into  a  bucket ;  the 
second  is  then  opened,  and  afterwards  the  third,  and  the 
indigo  which  the  water  carries  off  is  allowed  to  precipitate 
itself. 

As  the  earthy  deposit  which  is  formed  at  the  bottom  of 
the  vat  contains  some  indigo,  it  is  washed  in  a  great  quan- 
tity of  water,  which  is  drawn  off  in  the  same  way  as  the 


EXTRACTION    OF    INDIGO    FROM   WOAD.  311 

first,  this  being  repeated  till  no  more  indigo  can  be  ob- 
tained from  the  deposit. 

Notliing  more  is  necessary  to  be  done  to  the  paste  of 
indigo  when  it  has  been  freed  from  all  foreign  substances, 
than  to  separate  from  it  the  water  which  renders  it  of  the 
consistency  of  porridge  ;  and  for  this  purpose  I  shall  pro- 
pose a  method  which  I  have  practised  successfully  in  some 
analogous  operations.  Line  the  inside  of  a  basket  with  a 
coarse  bag  of  woollen  or  tow  cloth,  throw  the  paste  into 
the  bag,  and  leave  it  to  drain.  When  filtration  is  ended, 
cover  the  paste  with  the  upper  end  of  the  bag,  which  had 
been  turned  down,  and  place  upon  it  a  large  round  wooden 
dish,  which  will  fit  the  inside  of  the  basket,  and  upon  this 
put  a  weight,  which  is  to  be  gradually  increased  till  the 
fecula  acquires  a  great  degree  of  closeness  of  texture : 
if  the  operation  be  well  performed,  the  mass  can  scarcely 
be  broken  by  the  hand.  This  cake  is  afterwards  cut  into 
squares,  and  dried  at  a  temperature  of  between  30°  and 
40°.  (Probably  of  Reaumur,  and  equal  to  99°  and  122° 
of  Fahrenheit.)  The  preparation  of  indigo  is  afterwards 
terminated  by  an  operation  which  is  called  sweating. 

M.  de  Puymaurin  states,  that  the  most  favorable  time 
for  operation  is  when,  ^^  upon  breaking  an  angle  of  one  of 
the  cubes,  a  dry  noise  is  heard."  When  this  is  the  case, 
the  cakes  of  indigo  are  put  into  a  large  barrel  till  it  is 
full,  when  the  top  is  covered,  without  having  the  head 
fastened  in.  The  indigo  remains  in  this  cask  three  weeks, 
during  which  time  it  heats  and  gives  out  a  disagreeable 
odor,  it  transpires  a  portion  of  water,  and  becomes  covered 
with  a  white  down.  At  the  end  of  the  specified  time  the 
surface  of  the  indigo  is  rubbed  and  smoothed,  and  it  is 
then  prepared  for  sale. 

The  indigo  of  woad,  if  prepared  with  all  the  care  here 
described,  is  equal,  if  not  superior  to  the  best  of  that 
brought  from  Guatimala;  its  effects  are  the  same  in  dy- 
ing, and  it  differs  from  that  neither  in  nature  nor  in  char- 
acteristics. By  the  manufacture  of  this  kind  of  indigo  in 
France,  a  new  source  of  agricultural  prosperity  may  be 
bestowed  upon  her. 

It  now  only  remains  to  be  determined  whether  or  not 
the  farmer  can  with  advantage  turn  his  attention  to  the 
manufacture  of  woad-indigo ;  for  without  this,  though  the 
discovery  of  the  possibility  of  extracting  indigo  from  the 
isatis  would  be  in  itself  an  important  one,  it  would  be  of 
no  use  tn  the  nation. 


312  CHYMISTRY    APPLIED    TO    AGRICULTURE; 

If  it  should  be  ascertained  that  this  manufacture  would 
be  advantageous  in  peaceful  times,  it  certainly  must  be  re- 
garded as  of  great  importance  at  those  periods,  when  a 
maritime  war,  by  increasing  the  difficulty  of  procuring 
foreign  indigo,  shall  cause  the  price  of  it  in  commerce  to 
be  greatly  enhanced.  Besides,  if  good  king  Henry  IV. 
was  willing  to  pronounce  penalty  of  death  upon  the  im- 
porters of  indigo,  in  order  that  he  might  preserve  to  agri- 
culture the  manufacture  of  woad  cakes,  why  should  not 
government  prohibit  the  importation  of  the  same  article  as 
soon  as  the  manufacture  of  it  from  woad  is  established  ? 
France  would,  by  such  a  course,  be  endowed  with  a  pro- 
duct of  the  value  of  at  least  20,000,000  :  she  would  be 
placed  above  the  chances  of  war,  would  retain  within  her- 
self an  immense  sum  which  passes  into  foreign  hands,  and 
would  furnish  employment  to  the  numerous  population  of 
the  fields. 

But  let  us  see  if,  in  the  actual  state  of  things,  the  manu- 
facture of  woad  indigo  can  compete  with  the  importation 
of  it. 

An  acre  of  land  (old  Paris  measure)  produces  at  the 
various  cuttings  7^  tons  of  woad  leaves.  At  the  lowest 
calculation,  the  product  of  an  acre  in  leaves,  especially 
in  the  south,  may  be  fixed  at  7^  tons,  and  that  of  the  in- 
digo which  they  will  yield,  at  three  ounces  per  hundred 
weight,  will  make  nearly  28  lbs.  of  indigo  per  acre. 

The  value  of  good  indigo  may  be  estimated  at  nine 
francs  (a  franc  being  about  eighteen  or  nineteen  cents), 
and  this  will  make  the  value  of  the  indigo  from  an  acre  of 
land  to  be  252  francs.  Let  us  now  compare  this  with  the 
value  of  wheat  raised  upon  the  same  land  :  the  quantity 
of  wheat  may  be  estimated  at  about  12  hectolitres  (  =  34 
bushels),  and  the  price  at  eighteen  francs;  this  will  give 
215  francs  per  acre.  We  will  now  calculate  and  compare 
the  expense  attendant  upon  the  cultivation  of  each  plant. 

The  preparation  of  the  ground  by  tillage  and  manures 
is  the  same  for  the  seeds  of  both  plants,  but  the  expense 
of  cultivation  and  of  hand-labor  differ  essentially. 

Weeding  by  the  hand  is  sufficient  for  wheat,  and  the 
expense  of  this  is  very  trifling,  whilst  the  same  operation 
when  performed  upon  woad,  to  which  it  is  much  more 
necessary,  must  be  done  with  instruments  which  will 
loosen  the  earth,  and  root  out  all  the  noxious  herbs  :  the 
expense  of  this  cannot  be  estimated  at  less  than  twenty- 
five  francs. 


EXTRACTION    OP    INDIGO    FROM    WOAD.  313 

The  cutting  of  the  leaves,  which  must  be  repeated  five 
or  six  times,  amounts  during  a  season  to  about  fifty  francs. 

The  expenses  attendant  upon  the  manufacturing  pro- 
cesses cannot  be  estimated  at  less  than  two  francs  per 
pound  of  indigo  ;  this  will  make  fifty-six  francs. 

The  seed  necessary  for  sowing  an  acre  costs  about 
twelve  francs,  but  by  leaving  the  roots  in  the  ground  to  pro- 
duce seed,  this  may  be  reduced  to  -six  francs. 

Thus,  from  the  gross  product,  in  indigo,  of  two  hun- 
dred and  fifty-two  francs,  there  must  be  deducted 

francs. 

for  weeding 25 

"   cutting        50 

"    expense  of  manufacturing.  56 

"   seed        6 

137 

Deducting  this  from  252  francs,  there  will  remain  a  net 
product  of  115  francs,  (equal  to  between  $21  and  $23.) 

The  expenses  attendant  upon  cultivating  and  harvesting 
wheat  are  not  so  great  as  those  for  woad  ;  for,  stating  the 
price  of  seed  at  ^  of  the  value  of  the  product,  and  the 
weeding,  reaping,  gathering  in,  and  threshing,  at  ^,  the 
whole  expense  would  be  but  sixty-three  francs,  and  this 
reduces  the  net  value  of  the  product  to  one  hundred  and 
sixty-three  francs ;  the  balance  would  thus  be  in  favor  of 
the  cultivation  of  wheat. 

It  must,  however,  be  remembered,  that  I  stated  the  value 
of  the  product  in  indigo  at  the  lowest.  M.  de  Puymaurin 
has  obtained  five  ounces,  and  that  of  a  good  quality,  from 
1  cwt.  of  leaves  ;  at  this  rate  an  acre  of  land  would  yield 
forty-seven  pounds  of  indigo,  instead  of  twenty-eight ;  and 
this  sold  in  commerce  even  at  the  low  price  of  six  francs, 
would  produce  two  hundred  and  eighty-two,  instead  of 
two  hundred  and  fifty-two  francs.  An  additional  profit  like- 
wise arises  from  the  cakes  into  which  the  leaves  are  formed 
after  having  been  nearly  exhausted  of  their  indigo  ;  these 
may  be  sold  with  advantage  to  the  dyers,  or  if  there  be  no 
demand  of  this  kind  for  them,  they  form  a  better  and  more 
abundant  manure  than  that  which  is  yielded  by  the  dried 
stalks  and  leaves  of  wheat. 

I  may  likewise  add,  that  in  those  establishments  which 
are  in  the  vicinity  of  dye-houses,  the  indigo  paste,  which 
27 


314  CHTMISTRY    APPLIED    TO    AGRICULTtrKF. 

produces  the  same  effect  as  the  indigo  cakes,  may  be  sold', 
and  thus  the  manufacturer  may  save  himself  the  perform- 
ance of  the  three  principal  operations,  filtration,  drying, 
and  sweating  ;  and  the  dyer  will  be  spared  the  trouble  of 
breaking  the  cakes.  I  am  even  assured,  that  by  making 
use  of  the  fecula^  instead  of  the  indigo,  which  has  gone 
through  all  the  processes,  the  dyer  can  diminish  the  quan- 
tity of  woad  cakes  which  he  uses  in  the  composition  of 
his  coloring  liquor. 

It  seems  very  evident  to  me  that  the  introduction  of  this 
Yaluable  branch  of  industry  into  our  country,  needs  only 
some  slight  encouragement  on  the  part  of  government ; 
the  only  one  I  would  ask  is,  the  augmentation  of  the  pres- 
ent duty  upon  imported  indigo  of  ten  francs  per  kilo- 
gramme, (about  80  cts.  per  lb.)  Without  this,  the  agri- 
culturist can  hardly  determine  to  undertake  a  manufac- 
ture, which,  though  promising  advantage,  is  new  to  him^ 
and,  if  badly  conducted,  presents,  like  all  others,  danger 
of  loss. 

I  shall  conclude  this  chapter  by  inviting  all  agricul- 
turists who  are  zealous  for  the  progress  of  their  art,  to 
undertake  the  cultivation  of  the  isatts  tinctoria  upon  a 
very  small  portion  of  their  ground,  and  in  a  soil  suited 
to  it,  for  the  purpose  of  making  indigo  j  they  may  in 
this  way  familiarize  themselves  with  the  processes  of  the 
manufacture  so  as  to  be  able  to  enter  into  it  upon  a  large 
scale  with  confidence. 

The  isatis  grows  and  prospers  in  all  climates ;  that  which 
is  raised  in  the  northern  departments  of  our  country  has 
been  known  to  yield  five  ounces  per  cwt.  which  corresponds 
to  the  quantity  afforded  by  it  in  the  south. 

It  would  be  wrong  to  be  discouraged  in  any  undertaking 
by  the  failure  of  a  first  attempt ;  neither  in  cultivation 
nor  in  manufacturing  can  one  hope  to  arrive  at  perfection 
at  once  ;  time,  experience,  and  especially  close  observa- 
tion, can  alone  enable  us  to  overcome  all  obstacles,  and 
so  to  manage  our  concerns  as  to  be  always  sure  of  suc- 
cess. The  experiments  which  I  recommend  are  not  costly, 
neither  do  they  require  any  other  utensils  than  are  to  be 
found  in  every  farm  house. 


CULTIVATION  OF  THE  BEET  ROOT.         31S 


CHAPTER  XXI. 

ON  THE  CULTIVATION  OF  THE  BEET  ROOT,  AND  THE  EX- 
TRACTION OF  SUGAR  FROM  IT. 

I  FEEL  myself  authorized  by  ten  or  twelve  successive 
years  of  experiments  and  observations  upon  the  cultiva- 
tion of  the  beet  root,  and  the  extraction  of  sugar  from  it, 
to  publish  some  results  which  may  be  relied  upon. 

As  this  new  branch  of  industry  is  capable  of  being  ren- 
dered a  fruitful  source  of  agricultural  prosperity,  I  shall 
be  pardoned  if  I  enter  into  all  those  details  which  I  con- 
sider necessary  for  directing  the  agriculturist,  that  he  may 
not  try  such  experiments  and  commit  such  mistakes,  as 
often  lead  to  useless  expense  and  are  always  discouraging- 


SECTION  L 
On  THE  Cultivation  of  the  Beet  Root< 

Beet  seed  is  sown  in  the  latter  part  of  April  and  the 
beginning  of  May,  when  there  is  no  longer  any  danger  of 
the  return  of  frost.  I  have  sown  it  with  good  success 
towards  the  middle  of  the  month  of  June  ;  it  is  better, 
however,  to  sow  it  neither  too  early  nor  too  late.  If  it  be 
sown  immediately  after  the  cessation  of  the  frosts,  the 
ground  being  cold  and  very  wet,  the  seed  does  not  germi- 
nate immediately,  and  the  soil,  becoming  hardened  by  the 
violence  of  the  rains,  does  not  admit  the  air  to  penetrate, 
so  that  if  the  seed  do  not  decay,  the  beets  come  up  badly; 
when  sown  late,  they  suffer  from  evils  of  another  descrip- 
tion ;  the  rains  will  then  be  less  frequent,  but  the  great 
heat  dries  up  the  ground,  and  those  soils  that  are  rich  and 
compact  form  a  crust,  which  the  tender  plumule  of  the  beet 
cannot  pierce.  Those  seeds  which  are  sown  at  the  right 
season  have  to  encounter  the  danger  of  being  stifled  by  a 
host  of  strange  plants  that  spring  up  with  them,  and  which 
render  weeding  very  expensive.  The  most  favorable  period 
is  that  when  the  earth,  although  heated  by  the  rays  of 
the  sun,  still  contains  sufficient  moisture  to  produce  ger- 


316  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

raination,  and  to  facilitate  the  growth  of  the  young  plant  : 
the  last  days  of  April  and  the  first  fifteen  days  of  May 
generally  unite  these  advantages. 


ARTICLE  I. 

On  the  Choice  of  Seed. 

A  GOOD  agriculturist  should  always  raise  his  own  seeds : 
for  this  purpose  he  will  plant  his  beet  roots  in  the  spring 
in  a  good  soil,  and  gather  the  seed  in  September  as  fast  as 
it  ripens,  selecting  only  the  besfc,  and  leaving  upon  the 
stalks  such  as  are  not  thoroughly  ripe  ;  each  beet  root  will 
furnish  from  five  to  ten  ounces  of  seeds. 

When  no  care  is  taken  in  selecting  the  seeds,  and  they 
are  sown  indiscriminately,  not  only  are  many  of'  the  beets 
small,  and  ill  grown,  but  half  of  the  seeds  sown  do  not 
yield  any  thing. 

Beets  vary  in  color,  some  being  white,  others  yellow, 
red,  or  marbled ;  there  are  even  some  of  which  the  skins 
are  red  and  the  substance  white  :  it  is  generally  known,' 
that  seed  from  a  beet  of  one  color  does  not  always  produce 
the  like  :  a  field  which  is  sown  with  the  seeds  of  yellow 
beets  alone,  will  invariably  yield  some  roots  of  the  other 
colors. 

Too  much  importance  has  hitherto  been  affixed  to  the 
color  ;  I  have  never  myself  observed  any  considerable  dif- 
ference in  the  products  of  the  different  kinds  ;  however,  I 
cultivate  from  preference  the  yellow  and  the  white,  be- 
cause the  process  of  refining  the  sugar  made  from  red  beets 
requires  a  little  more  time  ;  for  although  the  lime  which  is 
employed  in  the  first  operation  instantly  deprives  the  juice 
of  color,  yet  it  acquires,  during  concentration  in  the  boiler, 
a  brownish  tinge,  which  the  sirup  from  white  and  that  from 
yellow  beets  does  not  receive. 


CULTIVATION  OF  THE  BEET  BOOT.         317 

ARTICLE    II. 
On  the  CJioice  of  SoiL 

All  corn  lands  are  more  or  iess  adapted  to  the  cultiva^ 
tion  of  beets ;  but  the  best  soils  for  the  purpose  are  those 
that  have  the  greatest  depth  of  vegetable  mould, 

Sandy  soils  formed  by  alluvions  and  the  deposits  of 
rivers  are  also  very  favorable  to  the  growth  of  beets ;  nor 
is  any  other  artificial  manure  necessary  upon  spots  so 
situated  as  to  receive  it,  than  the  mud  which  is  periodically 
deposited  by  inundations. 

Beets  may  be  cultivated  with  good  success  upon  natural 
or  artificial  grass  lands;  but  I  have  always  observed,  that 
beets  came  up  badly  when  sown  in  the  spring  upon  such 
lands  as  had  been  broken  up  in  the  autumn,  and  ploughed 
two  or  three  times  during  the  winter  :  the  turf  and  roots 
do  not  in  so  short  a  time  become  sufficiently  decomposed ; 
and  in  order  to  have  good  beet  roots,  I  find  it  necessary  to 
raise  a  crop  of  oats  between  the  time  of  breaking  up  a 
meadow  and  sowing  it  with  beet  seed  :  after  this  I  can 
raise  two  successive  crops  of  the  finest  beets.  If  the  soil 
of  a  natural  grass  land  is  dry,  or  not  closely  united,  it  may 
be  sown  with  beet  seed  six  months  after  being  broken  up  ; 
but  I  have  never  obtained  good  harvests  of  beets  from  clo- 
ver lands  without  having  first  sown  them  with  a  crop  of 
grain  :  in  these  lands  the  beets  have  always  been  better 
the  second  year  than  the  first. 

Dry,  calcareous,  and  light  soils  are  but  little  suited  to 
the  culture  of  this  root. 

Strong  clayey  soils  are  not  well  adapted  to  the  cultiva- 
tion of  beets  ;  in  order  that  these  roots  may  prosper,  it  is 
necessary  that  they  should  grow  in  a  loose,  fertile  soil,  hav- 
ing a  bed  of  vegetable  mould  of  at  least  twelve  or  fifteen 
inches  in  depth. 

Beets  prosper  to  a  certain  extent  in  all  arable  lands, 
but  the  quantity  as  well  as  quality  of  the  product  varies 
surprisingly  with  the  nature  of  the  soil.  Good  soil  will 
furnish  100,000  lbs.  per  hectare,  (=  2  acres,  1  rood,  35 
perches  English ;)  a  poor  soil  only  from  10,000  to  20,000 
lbs. 

Upon  several  hectares  of  lands  of  very  different  nature, 
27* 


318  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

which  I  put  in  (jultivation  each   year,  the  average  rate  of 
production  is  40,000  lbs. 

The  value  of  beets  cannot  be  calculated  by  the  gross 
weight ;  the  large  roots,  which  often  weigh  from  ten  to 
twenty  pounds,  contain  a  large  proportion  of  water,  and  the 
specific  gravity  of  the  juice  extracted  from  such  will  not  be 
more  than  5^or  6°  of  the  hydrometer  (=  1.036  to  1.044,) 
whilst  that  of  beets  weighing  a  pound  less  will  rise  as  high 
as  8°  or  10°  (=  1.060  to  1075,)  so  that  the  juice  of  the  last 
contains  in  the  same  volume  nearly  twice  as  much  sugar 
as  does  that  of  the  first,  and  the  extraction  of  it  is  easier 
and  less  expensive,  because  less  time  and  fuel  are  required 
for  evaporation.  I  therefore  prefer,  in  my  manufactory, 
beets  which  weigh  one  or  two  pounds,  though  the  soil  up- 
on which  I  raise  them  should  not  yield  me  more  than  from 
25,000  to  30,000  lbs.  per  hectare. 


ARTICLE  III. 
On  the  Preparation  of  the  Soil. 

Generally  speaking,  I  cultivate  beets  upon  all  such 
lands  as  are  appropriated  for  sowing  grain  upon  in  the  fall. 
The  lands  I  prepare  for  receiving  the  seed  by  three  good 
tillings,  two  of  which  are  performed  in  the  winter,  and  one 
in  the  spring  :  by  this  last  ploughing  the  dung  which  is 
thrown  upon  the  ground  after  the  second,  is  mixed  with  it : 
the  quantity  of  manure  employed  is  the  same  as  if  the 
ground  was  to  be  immediately  sown  with  wheat. 

When  the  cultivation  of  the  beet  was  less  known  than 
it  is  at  present,  it  was  thought  that  the  use  of  dung  rendered 
the  root  less  rich  in  sugar,  and  more  disposed  to  produce 
salt-petre ;  my  own  observations  have  never  verified  the 
truth  of  this  opinion,  nor  have  I  ever  perceived  any  other 
difference  than  that  of  size  between  beets  raised  in  ground 
dressed  with  barn-yard  manure,  and  those  raised  in  a  soil 
not  so  prepared.  That  which  has  given  rise  to  the  error 
is  the  greater  quantity  of  sugar  contained  in  the  same  vol- 
ume of  small  beets,  in  consequence  of  the  more  concen- 
trated state  of  their  juices. 


CULTIVATION  OF  THE  BEET  ROOT.         319 

ARTICLE  IV. 

On  the  Manner  of  Sowing  Beet  Seed. 

Beet  seed  may  be  sown  in  either  of  the  three  following 
methods.  1.  in  a  seed  plot:  2.  in  drills:  3.  broad-cast. 
The  first  of  these  ways  offers  to  the  agriculturist  the  ad- 
vantage of  requiring  much  the  least  time  at  a  season  of  the 
year  when  every  moment  is  precious :  the  young  plants 
may  be  transplanted  in  June  before  the  commencement  of 
the  hay  harvest,  so  that  the  cultivation  of  beets  need  not  in 
any  way  impede  the  ordinary  labors  of  the  fields.  There 
are  however,  some  serious  inconveniences  attendant  upon 
this  mode  of  sowing :  the  first  of  these  is  the  care  that  is 
requisite  in  pulling  up  the  young  plants  so  as  not  to  leave 
behind  a  portion  of  the  root ;  for  if  a  tap-root  be  broken 
off,  it  ceases  to  increase  in  length,  but  grows  in  circum- 
ference, and  throws  out  radicles  from  its  surface  in  every 
direction.  The  second  difficulty  is,  that  if,  in  placing  the 
root  in  the  earth,  its  long  and  very  slender  point  be  bent 
upward,  its  growth  in  length  is  frustrated  in  the  same 
manner  as  if  it  were  broken  off.  It  is  however  advisable  for 
the  farmer  to  sow  a  portion  of  his  beet  seed  in  a  seed  plot, 
in  order  that  he  may  be  able  to  fill  the  vacancies  which 
will  always  be  found  in  fields  sown  by  the  other  methods. 

But  seed  may  bie  sown  broad-cast  in  the  same  man- 
ner as  grain,  and  in  this  case  sowing  may  be  com- 
menced as  soon  as  the  ground  has  been  well  prepared  by 
ploughing  and  rolling.  -The  seed  is  covered  by  having  a 
harrow  passed  over  the  ground  in  two  directions,  crossing 
each  other.  This  method  requires  at  least  from  eleven 
pounds  and  a  half,  to  thirteen  pounds  and  a  half  of  seed 
per  hectare. 

This  last  process  is  the  one  most  generally  made  use  of, 
and  the  one  which  I  myself  employed  during  seven  or  eight 
years ;  but  I  now  give  the  preference  to  the  method  of 
sowing  in  drills,  as  being  more  sure  and  more  economical. 
For  this  purpose,  as  soon  as  the  ground  is  prepared,  I  trace 
upon  the  surface,  by  means  of  a  harrow  ^rmed  with  four 
teeth,  distant  about  eighteen  inches  from  each  other,  fur- 
rows of  an  inch  in  depth  ;  the  seed  is  dropped  into  these 
furrows  at  intervals  of  sixteen  inches,  by  women  or  girls 
who  follow  the  harrow,  and  who  cover  the  earth  over  the 


320  CHYMISTRY  APPLIED    TO   AGRICULTURE. 

seeds  with  their  hands.  Each  woman  can  sow,  in  this 
manner,  six  or  eight  thousand  seeds  in  a  day. 

The  quantity  of  seed  necessary  in  this  method,  is  a  little 
less  than  half  what  is  required  for  sowing  broad-cast,  and 
the  weeding  of  the  beets  is  much  easier,  and  by  no  means 
60  expensive. 

The  method  of  sowing  beet  seed  which  has  been  adopt- 
ed in  England,  can  scarcely  fail .  of  being  successful :  it 
consists  in  opening  a  deep  furrow,  in  the  bottom  of  which 
is  placed  a  portion  of  the  manure  which  is  to  be  used  upon 
the  land  ;  a  second  furrow  is  then  drawn  parallel  to  the 
first,  and  so  near  it  that  the  earth  thrown  up  shall  cover 
that  over :  the  second  trench  is  prepared  in  the  same  man- 
ner as  the  first,  and  so  on  ;  the  seeds  being  sown  immedi- 
ately over  the  manure.  By  this  disposition  of  the  ground 
the  roots  easily  penetrate  through  the  loose  soil  to  the  dung, 
which  retains  its  moisture,  and  furnishes  the  plants  with 
nourishment. 

But  whatever  mode  may  be  followed  in  sowing  beet  seed, 
it  is  necessary  to  observe  the  three  following  rules :  first, 
to  sow  only  new  and  naturally  fertile  soils  ;  second,  not  to 
place  the  seed  at  the  depth  of  more  than  an  inch ;  third, 
not  to  sow  the  seeds  too  thickly. 


ARTICLE  V. 

On  the  Care  required  hy  Beets  during  their  Vegetation, 

There  are  few  plants  that  require  more  care  than  beets  : 
their  developement  is  greatly  impeded  by  the  neighbour- 
hood of  other  plants,  and  if  the  soil  be  not  light  and  loose 
around  them,  they  languish,  turn  yellow,  and  cease  to 
grow. 

When  beet  plants  begin  to  show  their  second  leaves, 
they  must  be  weeded  :  if  they  have  been  sown  broad-cast, 
this  can  be  done  only  by  the  hand  or  with  a  small  hoe  or 
weeding  fork  ;  all  the  weeds  must  be  rooted  up,  and  as 
many  of  the  plants  removed  as  will  leave  spaces  of  eigh- 
teen inches  between  those  that  remain.  If  the  plants  are 
sown  in  furrows,  the  plough  may  be  passed  between  the 
rows,  and  the  roots  of  the  plants  be  cleared  with  the  weed- 


CULTIVATION  OF  THE  BEET  ROOT.         321 

ing  fork.  The  same  operation  must  be  repeated  at  least 
twice  in  a  season. 

As  weeding  opens  the  earth  to  the  free  entrance  of  air 
and  water,  the  plants  may  be  seen  to  be  benefited  by  it ; 
the  green  of  their  leaves  deepens,  their  roots  increase  in 
size,  and  their  foliage  expands. 

Since  I  have  sown  my  fields  in  drills,  I  have  practised 
passing  the  plough  through  them  three  times  in  the  course 
of  a  summer,  and  at  each  time  I  have  made  thorough  use 
of  the  weeding-fork  around  the  roots  of  the  plants. 

Half  a  day's  use  of  the  plough  is  sufficient  for  half  a 
hectare,  and.  the  rest  may  be  completed  in  a  day  by  five  or 
six  men.  I  find  that  I  save  one  half  the  expense  of  weed- 
ing by  employing  this  method.  Each  weeding  with  the 
fork  costs  at  least  twenty  francs  per  acre.  The  produce 
of  a  field  which  is  well  taken  care  of,  is  at  least  double  that 
of  one  which  is  neglected. 


ARTICLE  VI. 
On  the  Gathering  of  Beet  Roots. 

Beet  roots  are  generally  dug  during  the  month  of  Octo- 
ber :  the  digging  should  be  completed  before  the  com- 
mencement of  the  frosts.  When  surprised  by  untimely 
frosts,  if  the  roots  cannot  readily  be  transported  to  a  place 
of  shelter,  they  may  be  collected  in  heaps  upon  the  fields 
and  covered  over  with  their  own  leaves  :  those  that  remain 
in  the  earth  are  in  much  less  danger  from  frost  than  those 
that  have  been  dug. 

The  time  mentioned  in  the  preceding  paragraph  is  the 
one  most  suitable  for  the  vicinity  of  Paris,  and  for  the 
centre  of  France  ;  but  as  vegetation  is  more  forward  in  the 
southern  departments,  it  is  necessary  that  beets  should 
there  be  gathered  earlier  in  the  season,  otherwise  the  sac- 
charine principle  may  disappear,  in  consequence  of  a  new 
elaboration  of  the  juices  after  maturity  The  fact  appears 
to  me  to  have  been  fully  ascertained  by  the  experiments  of 
M.  Darracq.  This  able  chymist,  in  concert  with  the  Count 
Dangos,  Prefect  of  the  Department  of  Landes,  made  every 
arrangement  for  the  establishment  of  a  sugar  manufactory. 


322  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

During  the  months  of  July  and  August,  he  made  experi- 
ments upon  beets  every  eight  days,  and  always  obtained 
from  three  and  a  half  to  four  per  cent,  of  good  sugar. 
Satisfied  with  these  results,  he  discontinued  his  experiments, 
in  order  to  devote  all  his  time  to  the  care  of  his  establish- 
ment ;  but  how  great  was  his  surprise  at  finding  towards 
the  end  of  October  that  his  beets  yielded  only  sirup  and 
salt-petre,  and  not  a  particle  of  crystallizable  sugar. 

Generally  speaking,  beets  may  be  dug  as  soon  as  their 
largest  leaves  begin  to  turn  yellow.  If  harvested  before 
arriving  at  maturity,  they  wither,  wrinkle,  and  grow  soft : 
the  juice  is  extracted  from  them  in  this  state  with  more 
difficulty,  and  the  sugar  does  not  grain  so  well. 

The  leaves,  which  are  separated  from  the  roots  as  fast 
as  they  are  taken  from  the  ground,  may  be  left  upon  the 
spot  and  there  eaten  by  cows,  sheep,  or  swine;  but  they 
are  so  abundant  that  there  will  still  remain  enough  to  serve 
as  a  half  manure  for  the  land,  and  it  is  in  this  soil,  after 
having  slightly  ploughed  it,  that  I  sow  my  grains.  As  the 
earth  has  been  manured  in  the  spring,  and  afterwards  freed 
from  weeds  by  repeated  hoeings,  the  corn  will  grow  very 
large  and  be  very  clean ;  so  that  the  first  tillage  and  ma- 
nuring serve  for  two  harvests,  and  the  ploughings  which 
are  given  in  autumn  to  lands  appropriated  to  the  reception 
of  wheat  or  rye,  are  saved. 


ARTICLE  VII. 

On  the;  best  Method  of  Keeping  Beet  Roots. 

Beets  are  affected  both  by  cold  and  heat :  they  freeze 
at  a  temperature  one  degree  below  the  freezing  point  of 
water,  and  they  germinate  with  a  degree  of  heat  but  little 
above  freezing  :  freezing  softens  them  and  destroys  their 
saccharine  principle,  and  they  decay  as  soon  as  they  are 
thawed.  Heat  developes  the  stalks  at  the  necks  of  the 
roots,  and  decomposes  the  juices  which  supply  their  growth. 
During  the  first  stages  of  germination,  the  alteration  of  the 
juices  is  only  local ;  so  that  if  the  neck  of  the  root  be  cut 
off,  the  remainder  of  it  may  be  made  use  of  without  any 
inconvenience.  In  order  to  keep  beets,  it  is  necessary  to 
preserve  them  both  from  heat  and  cold. 


CULTIVATION  OF  THE  BEET  ROOT.  323 

The  first  care  of  the  farmer  must  be,  to  have  his  beets 
thoroughly  dry  before  being  housed.  The  best  way  is  to 
leave  them  in  the  fields  till  all  their  dampness  has  evapo- 
rated. When,  however,  a  large  harvest  is  to  be  gathered 
in  autumn,  a  sufficient  number  of  fine  days  to  effect  this 
can  hardly  be  hoped  for,  and  the  roots  must  therefore  be 
stored  for  the  winter  in  such  a  manner  as  will  be  most  likely 
to  prevent  decomposition. 

I  have  an  immense  barn,  where  I  pile  up  my  beets  to  the 
height  of  seven  or  eight  feet,  as  fast  as  they  are  carried 
from  the  fields.  I  make  use  of  no  other  precaution  than 
that  of  forming  against  the  surrounding  walls  a  layer  of 
straw  or  broom,  which  rises  as  high  as  the  pile  of  roots ; 
when  the  frosts  set  in,  I  cover  the  pile  over  with  straw ;  and 
in  this  way  I  have  for  ten  years  preserved  my  crops  of  beets 
uninjured  by  them.  It  has,  however,  happened  two  or  three 
times,  that  the  roots  began  to  germinate  with  so  much 
energy,  that  I  was  fearful  they  would  become  decomposed. 
In  these  cases,  I  unstacked  and  spread  the  beets,  and  thus 
arrested  the  process  of  vegetation. 

Some  farmers  leave  their  beets  in  the  field.  In  order  to 
preserve  them,  they  dig  a  trench  in  a  dry  soil,  giving  the 
bottom  a  gentle  slope,  that  water  may  flow  off  easily.  This 
trench  they  fill  with  the  roots,  and  cover  it  over  with  a  bed 
of  earth  a  foot  thick  ;  upon  this  they  throw  heath  or  broom, 
to  prevent  the  rain  from  penetrating.  Some  line  the  bottom 
and  sides  of  the  trench  with  straw  or  heath. 

Instead  of  being  put  into  trenches,  the  digging  of  which 
is  always  expensive,  the  beets  may  be  preserved  in  the 
fields  by  forming  heaps  of  them  upon  a  dry  soil,  and  covering 
the  tops  and  sides  with  layers  of  earth ;  or  they  may  be 
covered  over  with  a  roof  like  the  one  I  have  heretofore 
described.  This  method  of  preserving  roots  may  be  em- 
ployed when  there  is  no  suitable  storehouse  for  them ;  or 
when  the  means  of  conveying  them  to  one  in  autumn  are 
wanting. 


324  CHYMISTRY    APPLIED    TQ    AGRICULTURE. 

SECTION  II. 

On  the  Extraction  of  Sugar  from  Beets. 

I  shall  not  here  describe  the  numerous  difficulties  that 
have  been  encountered  before  arriving  at  sure  methods 
and  certain  results.  I  shall  confine  myself  to  the  descrip- 
tion of  the  simplest  and  most  advantageous  processes  that 
are  employed  at  this  time ;  and  I  vi^ill  draw  my  examples 
from  my  own  practice,  enlightened  as  it  is  by  twelve  years 
of  experiment  and  observation.  I  have  successively  execu- 
ted all  the  known  processes ;  I  have  tried  all  the  improve- 
ments that  have  been  suggested ;  I  have  myself  regulated 
and  improved  some  of  the  processes ;  and  I  shall  describe 
only  such  as  I  have  proved  and  confirmed. 


ARTICLE  I 
On  the  Preparation  of  the  Roots. 

Before  subjecting  the  beets  to  the  teeth  of  the  rasp,  they 
must  be  carefully  freed  from  all  the  earth  which  they  bring 
with  them  from  the  fields.  The  necks,  and  any  portion 
that  has  begun  to  decay,  must  be  cut  off,  and  the  radicles 
removed  from  the  surface. 

In  many  manufactories,  nothing  more  is  done  to  the 
roots  than  to  wash  them.  But  this  operation  cannot  be 
conveniently  practised  in  all  places,  and  I  have  therefore 
dispensed  with  it  as  a  preliminary ;  nor  have  I  found  any 
bad  effect  to  arise  from  the  omission  of  it.  Eight  women 
can  easily  prepare  10,000  lbs.  of  the  roots  in  a  day.  It 
the  beets  are  large,  and  retain  but  little  earth  about  them, 
the  same  number  of  women  can  prepare  in  the  same  time 
from  15  to  20,000  lbs. 


EXTRACTION  OP  SCGAR  FROM  BEETS.        325 

ARTICLE  II. 
On  the  Method  of  Rasping  the  Beet  Roots 

The  beets,  when  well  cleansed,  are  submitted  to  the 
action  of  a  rasp,  by  which  their  fibrous  substance  is 
reduced  to  a  pulp.  The  rasp  is  worked  either  by  a  horse, 
or  by  a  stream  of  water.  The  rapidity  of  its  motion  should 
be  equal  to  four  hundred  revolutions  upon  its  axis  in  a 
minute. 

The  rasps  used  by  me,  are  sheet-iron  cylinders,  fifteea 
inches  in  length,  and  twenty-four  in  diameter,  having  their 
surfaces  furnished  with  ninety  iron  plates  armed  with  saw 
teeth,  and  fixed  by  screws  perpendicularly  to  the  axis  of 
the  cylinder  and  throughout  the  Whole  length  of  it. 

The  beets  being  pressed  against  the  rasp,  by  means  of  a 
piece  of  wood  held  in  the  hand,  are  immediately  torn  in 
pieces.  The  pulp  falls  into  a  box  lined  with  lead,  which 
is  placed  beneath.  The  table  upon  which  the  beets  des- 
tined to  the  rasp  are  placed,  is  so  near  the  instrument  as  to 
allow  only  sufficient  space  between  for  the  passage  of  the 
pulp. 

The  operation  of  rasping  must  be  conducted  expedi- 
tiously, otherwise  the  pulp  begins  to  turn  brown,  fermen- 
tation takes  place,  and  the  extraction  of  the  sugar  is 
rendered  difficult.  By  the  use  of  two  rasps,  put  in  motion 
by  the  same  horse,  I  have  reduced  5000  pounds  of  beets  to 
a  pulp  in  two  hours.  The  pulp  should  not  contain  any 
portion  of  roots  that  have  not  been  acted  upon  by  the 
instrument. 

Compression  will  not  in  any  degree  supply  the  place  of 
rasping.  The  strongest  presses  can  never  extract  from 
beets  more  than  from  ^  to  ■f'jpp  of  their  juice,  whilst  the 
pulp,  if  properly  managed,  will  yield  from  -j?^  to  -j^. 


ARTICLE  III. 

On  the  Extraction  of  the  Juice, 

As  fast  as  the  pulp  falls  into  the  box  placed  under  the 
rasps,  it  is  put  into  small  bags  made  of  very  strong  cloth 
28 


326  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

woven  of  pack-thread.  These  bags  are  placed  upon  the 
plate  of  a  good  iron  screw  press,  and  submitted  to  a  strong 
pressure.  The  screws  are  after  a  time  to  be  loosened,  the 
places  of  the  sacks  changed,  the  pulp  which  they  contain 
shaken  over,  and  the  whole  again  submitted  to  the  action 
of  the  screw. 

Sometimes  the  pulp  is  first  acted  upon  by  a  cylindrical 
press,  by  which  about  y^^^  of  its  juice  is  extracted,  and  the 
operation  is  afterwards  completed  by  means  of  the  screw 
press.  But  10,000  pounds  of  beets  may  be  pressed  in  a 
day  by  the  last  alone. 

The  pressure  should  be  continued  till  the  pulp  will  not 
moisten  the  hand  when  strongly  squeezed  in  it.  The 
juice  which  flows  from  the  press,  is  carried  by  leaden 
pipes  into  the  boiler,  where  it  undergoes  the  first  opera- 
tion.    Of  this  I  shall  speak  immediately. 

If  an  iron  screw  press  is  not  to  be  had,  a  wine  press,  a 
lever  press,  or  a  cylinder  press  will  answer  the  purpose. 

The  operation  of  the  press  should  be  completed  nearly 
at  the  same  time  with  that  of  the  rasp.  Every  thing  that 
has  been  moistened  with  the  juice,  must  then  be  washed 
so  as  to  be  ready  for  a  new  operation.  The  utmost  clean- 
liness must  be  preserved,  otherwise  the  rasps  will  become 
rusty,  the  juice  will  change,  and  the  boiling  will  be  rendered 
difficult. 

The  juice  extracted  from  beets,  is  not  always  of  the 
same  degree  of  concentration.  It  varies  from  5°  to  10°, 
(=  specific  gravity  of  1.036  to  1.075,)  according  to  the  size 
of  the  roots,  the  nature  of  the  soil  in  which  they  grew,  and 
the  state  of  the  atmosphere  during  vegetation. 

The  juice  of  the  large  roots  is  less  concentrated  than  that 
of  the  small  ones.  The  juice  of  such  as  grow  in  a  light 
soil,  and  have  been  exposed  to  heat  and  drought,  marks 
11°,  (=  specific  gravity  of  1.083;)  but  there  is  but  little 
of  it.  The  greater  the  specific  gravity  of  the  juice  is,  the 
greater  is  the  proportion  of  sugar  contained  in  it ;  and,  of 
course,  the  greater  is  the  saving  of  labor  in  the  extraction 
of  the  sugar. 


EXTRACTION  OF  SUGAR  FROM  BEETS.        327 

ARTICLE   IV. 
On  the  Purification  of  the  Juice. 

As  soon  as  the  boiler  which  receives  the  juice  is  one 
third  full,  the  lire  is  kindled;  and,  as  the  juice  continues 
to  flow,  the  heat  is  raised  to  65°  of  Reaumur,*  (z=  180f° 
of  Fahrenheit.)  Whilst  the  juice  is  heating,  some  milk  of 
lime  is  prepared,  by  pouring  gradually  some  warm  water 
into  a  bucket  containing  ten  pounds  of  lime.t 

As  soon  as  all  the  juice  has  passed  into  the  boiler,  and 
become  heated  to  the  degree  mentioned  in  the  last  para- 
graph, the  milk  of  lime  is  thrown  into  it,  the  greatest  care 
being  taken  to  stir  and  mix  them  well  together ;  after 
which  the  temperature  may  be  raised  to  the  boiling  point. 
As  soon  as  the  first  bubble  makes  its  appearance  through 
the  thick  glutinous  scum  which  rises  upon  the  top  of  the 
liquor,  the  fire  is  immediately  extinguished  by  throwing  a 
pailful  of  water  into  the  fire-place.  The  scum  thickens,  dries, 
and  hardens  by  rest.  The  juice  becomes  clear,  and  takes 
a  light  yellow  hue.  When  there  can  no  longer  be  seen  in 
it  particles  either  of  lime  or  mucilage,  the  scum  is  removed 
with  a  skimmer  and  thrown  into  a  bucket,  in  order  that 
the  juice  which  it  contains  may  be  expressed.  The  upper 
stop-cock  is  then  opened,  and  the  liquor  is  suffered  to  flow 
into  the  evaporating  boiler. 

The  juice  does  not  become  clear  in  less  than  an  hour, 
and  evaporation  ought  not  to  be  commenced  till  it  is  per- 
fectly limpid. 

*  I  have  worked  10,000  pounds  of  beet  roots  per  day,  at  two  operations 
of  5,000  pounds  each.  The  first  began  at  4  o'clock,  A.  M.,  and  the 
other  at  noon.  The  round  boiler,  which  received  the  juice  of  one  ope- 
ration, was  five  feet  and  six  inches  in  diameter,  and  three  feet  eight 
inches  in  depth.  1  had  a  separate  boiler  for  each  operation,  and  each 
boiler  had  two  stop-cocks,  one  close  to  the  bottom  and  the  other  five 
inches  above.  Between  these  two  boilers,  there  wore  two  vessels 
fifteen  inches  deep,  and  each  of  sufiicient  capacity  to  receive  all  the 
juice  of  an  operation.  In  these,  evaporation  is  carried  on.  The  rims 
of  all  these  boilers  should  be  very  wide,  so  as  to  cover  the  thickness 
of  the  wall  in  which  they  are  set. 

My  rasps  and  presses  are  placed  upon  the  first  floor,  in  order  that  the 
juice  may  flow  through  leaden  pipes  into  the  boilers,  which  are  upon 
the  ground  floor,  and  thus  save  the  labor  of  transportation.  By  this 
arrangement,  I  can  have  my  depuratory  boilers  so  much  raised,  that, 
upon  turning  the  stop-cocks,  the  juice  will  flow  into  the  evaporating 


t  My  boiler  contains  475*^  gallons  of  juice ;  so  that  I  employ  the  lime 
in  the  proportion  of  about  46  grains,  troy. 


32&  CHTRnSTRY   APPLIED    TO    AGRICULTURE. 

As  soon  as  all  liquor  above  the  level  of  the  upper  stop- 
cock has  passed  out,  the  second  stop-cock  is  turned  ;  and  if 
the  liquor  flowing  through  that  be  found  clear,  it  is  mixed 
with  the  first  portion.  If,  on  the  contrary,  it  appears  cloudy, 
the  stop-cock  is  again  closed  to  give  it  time  to  settle,  and 
k  is  not  made  use  of  till  towards  the  termination  of  the 
evaporation. 

The  deposit  which  is  formed  at  the  bottom  of  the  boiler^ 
renders  the  last  portion  of  the  juice  turbid.  But  as  soon 
as  this  is  seen  to  be  the  case^  that  which  remains  is  drawn 
off  into  the  bucket  containing  the  scum. 

The  deposit  which  is  formed  at  the  bottom  of  the  boiler, 
and  this  scum,  are  expressed  by  means  of  a  lever  press  of 
very  simple  and  cheap  construction,  and  which  is  very  easi- 
ly worked. 

I  place  a  cylindrical  willow  basket  upon  a  block  of  stone 
three  feet  square,  the  upper  surface  of  which  is  slightly 
inclined  and  furrowed  with  channels  an  inch  deep,  uniting 
i^n  a  common  centre  at  the  lowest  angle.  The  basket  is 
lined  with  a  bag  of  coarse  cloth,  the  end  of  which  turns 
back  and  hangs  down.  Into  this  bag  I  put  the  deposit 
and  scum  ;  then,  drawing  the  edges  of  it  together,  I  tie 
the  mouth  closely  with  a  pack-thread.  I  place  on  the  top 
a  wooden  trencher  of  the  diameter  of  the  inside  of  the 
basket.  This  I  load  with  several  square  pieces  of  wood, 
which  project  over  the  upper  part  and  serve  as  a  fulcrum 
for  the  lever.  When  things  are  thus  far  arranged,  I  pro- 
ceed to  adjust  the  lever,  which  is  five  feet  long.  This  is 
fixed  at  one  end  to  a  ring-bolt  which  passes  through  a 
stone.  The  other  end  I  load  with  weights  to  the  amount 
of  from  56  to  112  pounds,  increasing  them  at  pleasure,  so 
as  to  produce  a  gradual  and  constantly  increasing  pres- 
sure, which  may  be  rendered  as  powerful  as  is  necessary. 
The  juice  which  is  thus  forced  out,  flows  into  a  bucket 
and  is  thrown  into  the  evaporating  vessel. 

The  most  difficult  operation  to  be  performed,  is  that  of 
purifying  the  juice  ;  and  if  this  be  not  thoroughly  done,, 
the  processes  of  evaporation  and  graining  are  long  and 
troublesome  ;  the  juice  swells  and  bubbles  up  in  the  boiler, 
and  the  sugar  crystallizes  imperfectly  and  remains  mixed 
with  molasses.  The  lime  which  is  thrown  in  to  clarify  the 
juice  does  not  always  rise  to  the  top  with  the  scum,  by  a 
prolonged  period  of  rest  in  the  depuratory  boiler  ;  neither 
i£  it  always  precipitated.     It  sometimes  happens,  that>  not- 


EXTRACTION    OF    SUGAR    FROM    BEETS.  WSd 

withstanding  all  the  care  that  can  be  taken,  the  liquor 
remains  cloudy  ;  and  in  such  cases  it  is  always  in  vain  to 
look  for  good  results.  I  have  endeavoured  to  ascertain  the 
cause  of  these  accidents,  and  I  have  sought  to  remedy  the 
evil.  I  shall  report  here  only  what  appears  to  me  to  be 
fully  established  by  experiment  and  observation. 

The  juice  does  not  purify  well  if  the  beets  have  begun 
to  germinate  too  strongly,  or  if  they  have  begun  to  decay, 
or  have  been  frozen. 

When  the  operations  of  the  rasps  and  presses  are  con- 
ducted too  slowly,  so  that  the  juice  stands  five  or  six  hours 
before  being  purified,  decomposition  commences,  and  good 
results  are  never  obtained. 

If  all  the  utensils  employed  are  not  carefully  washed 
after  each  operation,  so  as  to  free  them  thoroughly  from 
the  juice  adhering  to  them,  the  labor  becomes  difllcult 
and  unsuccessful. 

I  found,  upon  one  occasion,  that  beets  which  had  been 
kept  in  a  cellar,  where  they  had  neither  frozen  nor  ger- 
minated, did  not,  when  subjected  to  experiment  in  March, 
yield  sugar.  They  appeared  perfectly  healthy,  though  a 
little  softer  than  those  that  had  been  kept  in  ba'-ns. 

If  the  first  operations  are  not  well  conducted,  the  results 
are  always  bad.  I  can  only  point  out  the  steps  that  can  be 
taken  to  prevent  this. 

Beets  that  have  been  well  kept,  may  be  worked  with 
equally  good  success  from  the  beginning  of  October  to  the 
end  of  March. 

When  the  juice  does  not  become  clear,  a  small  quantity 
of  sulphuric  acid  may  be  thrown  into  the  evaporating  ves- 
sel, a  little  before  the  liquor  begins  to  boil.  This  will 
remedy  any  trouble  arising  from  the  use  of  too  large  a 
quantity  of  lime.  It  will,  however,  be  useless,  if  the  faults 
proceed  from  an  altered  state  of  the  beet  juice. 

By  making  use  of  a  portion  of  animal  charcoal  to  clarify 
the  liquor,  the  evaporation  of  the  juice  and  the  graining  of 
the  sugar  is  sure  to  be  rendered  more  easy  ;  but  the  quan- 
tity of  sugar  obtained  is  very  small. 

The  lime  used  in  the  process  of  purification  combines 
with  the  mucilaginous  principle  of  the  beets,  and  neutral- 
izes the  malic  acid  contained  in  them  ;  after  this  operation, 
the  juice  weighs  1**  or  1.5°  less  than  before. 

28* 


330  CHYTWISTRY    APPLIED    TO    AGRICULTURE-, 


ARTICLE  V. 

On  the  Concentration  or  Evaporation  of  the   Purified 
Juice, 

As  soon  as  the  bottom  of  the  evaporating  vessel  is  covered 
with  juice,  the  fire  is  kindled,  and  ebullition  is  produced  as 
speedily  as  possible,  —  the  juice  which  continues  to  flow 
from  the  clarifying  boiler  supplying  the  loss  occasioned  by 
evaporation. 

When  the  boiling  juice  marks  5°  or  6°  (=  1.036  to  1.044) 
of  concentration,  a  portion  of  animal  charcoal  is  thrown  in,, 
and  this  is  continued,  the  quantity  being  gradually  increase 
ed,  till  the  juice  is  concentrated  to  20^,  (=  1.161.)  Sixty 
pounds  of  charcoal  are  used  in  this  manner,  for  a  quantity 
of  juice  equal  to  from  422  to  475  gallons. 

After  having  brought  the  liquor  to  the  twentieth  de- 
gree of  concentration,  the  boiling  is  continued  till  the 
sirup  marks  27°  or  28°  of  the  hydrometer,  (=  specific 
gravity  of  1.231  to  1.242.)  The  sirup,  being  mixed  with 
animal  charcoal,  requires  to  be  filtrated.  This  operation ^ 
as  it  is  usually  performed,  is  very  tedious,  and  sometimes 
becomes  impracticable ;  the  consistency  of  the  sirup  is  in- 
creased two  or  three  degrees  by  cooling,  and  the  pores  of 
the  filter  becoming,  in  a  short  time,  obstructed  by  the 
finely  divided  charcoal,  the  thickened  liquor  can  no  longer 
pass  through  them. 

To  obviate  these  inconveniences  I  place  a  large  willow 
basket  over  a  boiler  ;  into  the  basket  I  put  a  coarse  bag  of 
the  same  diameter,  but  about  two  feet  deeper.  I  pour 
the  thickened  sirup  into  the  bag  ;  for  some  minutes  filtra- 
tion goes  on  very  well,  but  as  the  liquor  grows  thick  in 
consequence  of  its  cooling,  filtration  slackens  and  at 
length  stops  ;  as  soon  as  1  perceive  this,  I  turn  the  borders 
of  the  sack  into  the  basket,  and  upon  them  place  a  wooden 
trencher,  which  I  gradually  load  with  cast-iron  weights 
till  the  necessary  pressure  is  produced ;  filtration  is  by  this 
means  completed  in  two  or  three  hours. 

The  charcoal  contained  in  the  sack  is  leached  with 
warm  water,  and  afterwards  submitted  to  the  lever  press,  to 
force  from  it  all  the  sirup  contained  in  it.  The  waters 
used  for  these  leachings  during  one  day,  are  the  next  day 
mixed  in  the  clarifying  boiler  with  the  juices  that  are  then 
prepared. 


EXTRACTION  OF  SUGAR  FROM  BEETS.         331 

The  conversion  of  the  juice  into  sirup  should  be  done 
as  speedily  as  possible ;  for  when  evaporation  is  slow  the 
liquor  becomes  pasty,  as  part  of  the  sugar  is  decomposed 
and  passes  to  the  state  of  molasses,  and  the  difficulty  of 
boiling  is  increased.  It  is  necessary  then  that  evaporation 
should  be  carried  on  with  violent  boiling,  and  for  this  rea- 
son the  boilers  made  use  of  should  be  broad  and  shallow, 
so  as  not  to  heat  only  layers  of  the  liquor,  and  in  order 
that  ebullition  may  tak«  place  at  once  through  the  whole 
mass  of  the  liquid  ;  the  furnaces  likewise  should  be  so 
built  as  to  heat  the  boilers  equally.  The  evaporation  of 
422  gallons  should  be  completed  in  four  hours. 

The  operation  is  known  to  be  good,  and  the  juice  to  have 
been  well  prepared,  when  ebullition  takes  place  without 
causing  the  liquor  to  swell  and  blister ;  when  there  ap- 
pears on  the  surface  only  a  brownish  foam,  the  bubbles  of 
which  disappear  immediately  upon  being  pressed  with  a 
spoon,  and  when  a  dry  sound  is  produced  by  striking  upon 
the  liquor. 

If,  on  the  contrary,  there  forms  a  whitish,  gluey  foam, 
which  does  not  subside,  the  operation  is  bad ;  evaporation 
requires  a  long  time,  and  the  boiling  is  difficult.  In  this  case 
a  little  butter  is,  from  time  to  time,  thrown  upon  the  sur- 
face to  quiet  the  effervescence ;  the  quantity  of  animal 
charcoal  is  increased,  and  the  fire  is  checked.  All  these 
palliatives,  however,  do  not  correct  the  radical  fault,  and 
such  appearances  always  presage  bad  results. 


ARTICLE  VI. 
On  Boiling  the  Sirup. 

The  sirups  prepared  over  night  are  the  next  day  dried 
to  extract  the  sugar  from  them. 

The  products  of  two  operations  upon  5000  beets  are 
mixed  together  in  a  boiler,  whence  they  are  taken  to  form 
four  successive  dryings  or  boilings.  One  fourth  part  of 
these  sirups  is  thrown  into  a  round  boiler,  forty  inches  in 
diameter  and  twenty  in  depth  ;  under  this  a  fire  is  kindled  ; 
the  liquor  is  made  to  boil,  and  the  boiling  continued  till  the 
operation  is  ended. 


333  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

The  process  is  judged  to  be  going  on  well  if  the  liquor 
exhibits  the  following  symptoms. 

1.  When  the  sirup  breaks  short,  and  the  bubbles  upon 
returning  into  it  produce  a  sensible  sound. 

2.  When  a  dry  sound,  like  that  produced  by  striking 
silk,  is  returned  from  the  surface  of  the  sirup  when  it  is 
struck  with  a  skimmer. 

3.  When  the  bubbles  of  foam  disappear  immediately 
upon  being  pressed  with  a  spoon.  The  boiling  is  always 
perfect  when  the  interior  surface  of  the  boiler  is  found,  af- 
ter the  operation  is  ended,  to  retain  no  trace  of  blackness; 

The  sirup  is  known  to  be  bad  by  the  following  signs  : 

1.  When  a  thick,  whitish,  gluey  foam  appears  upon 
the  surface  of  the  liquor. 

2.  When  the  liquor  swells  and  foams,  and  does  not 
subside. 

3.  When  the  escape  of  puffs  of  acid  steam  announces 
that  the  boiling  substance  is  burnt. 

The  evils  are  palliated  and  the  boiling  terminated, 

1.  By  removing  the  foam  as  fast  as  it  forms. 

2.  By  throwing  into  the  substance  small  pieces  of 
butter. 

3.  By  stirring  the  liquor  with  a  large  spatula. 

4.  By  mixing  with  it  a  little  animal  charcoal. 

5.  By  moderating  the  heat. 

To  avoid  a  portion  of  these  evils,  I  throw  a  flood  of 
sirup  into  the  boiler,  and  remove  the  whitish  foam  that 
arises ;  I  stir  the  sirup  strongly  three  or  four  times  before 
boiling  commences,  and  skim  it  each  time.  The  scum 
that  is  removed  is  thrown  into  a  bucket  with  that  which  is 
produced  during  all  the  time  that  the  liquor  is  boiling ; 
these  skimmings  are  afterwards  subjected  to  the  lever 
press,  and  the  remainder  washed,  to  obtain  from  it  all  the 
juice  contained  in  it.  The  sirup  obtained  by  pressing  up- 
on one  day,  is  added  to  the  liquor  that  is  boiled  the  next, 
and  the  water  of  the  leaching  is  thrown  into  the  evaporat- 
ing boiler. 

When  the  sirup  in  the  drying  vessel  shows  itself  to  be 
bad,  especially  when  it  gives  out  puffs  of  sharp  steam, 
which  declare  the  substance  to  be  burnt,  it  is  necessary  to 
arrest  the  process  and  to  treat  the  sirup  with  an  additional 
portion  of  animal  charcoal.  In  this  case  the  liquor  is  di- 
luted with  water  till  it  falls  to  18°  or  20°  of  concentra- 
tion, (=  specific  gravity  of  1.143  to  1.161,)  and  then  the 


EXTRACTION  OF  SUGAR  FROM  BEETS.        333 

charcoal  is  added ;  after  which  ebullition  is  renewed  till  the 
sirup  rises  to  28°,  (=:  1.24*2,)  when  it  is  filtered  and  dried. 
I  have  found  this  to  be  the  only  way  in  which  I 
could  restore  a  sirup  which  had  been  injured  in  the 
process. 

I  have  myself  made  particular  observations  upon  the 
thick,  whitish,  unctuous  and  paste-like  substance,  which 
is  almost  always  found  upon  the  sirup,  and  which,  when  it 
is  abundant,  prevents  the  drying  from  being  well-termi- 
nated. This  substance  renders  the  sirup  ropy,  adheres  to 
the  sides  of  the  boiler,  which  are  blackened  by  it,  separates 
itself  from  the  sirup,  in  proportion  to  its  concentration,  and 
prevents  the  object  proposed  from  being  attained. 

I  have  noticed  that  the  quantity  of  this  substance  was  in 
proportion  to  the  germination  of  the  roots,  and  that  it  was 
increased  by  the  incomplete  purification  of  the  sirup,  and 
also  by  a  slow  evaporation.  Animal  charcoal  produces  an 
astonishing  effect  in  lessening  the  quantity  of  it ;  sometimes, 
if  well  employed,  the  formation  of  it  is  prevented,  or  that 
which  is  produced  is  made  to  disappear. 

This  substance,  which,  during  the  first  years  of  my  es- 
tablishment, I  often  collected  in  large  quantities,  is  thick- 
ened and  hardened  by  cold;  it  is  insoluble  in  water  or 
alcohol ;  it  burns  with  a  white  and  inodorous  flame ;  and 
possesses  all  the  characteristics  of  vegetable  wax,  from 
which  it  is  in  no  wise  different. 

The  drying  is  ended  when  the  boiling  sirup  marks  44"* 
or  45°,  (=  specific  gravity  of  1.440  to  1.454.)  The  time 
for  removing  the  sirup  from  the  boiler  may  be  known  by  the 
following  signs. 

1.  Plunge  a  skimmer  into  the  boiling  sirup,  and  upon 
withdrawing  it  pass  the  thumb  of  the  right  hand  over  its 
surface ;  mould  the  sirup  which  adheres  to  the  thumb  be- 
tween that  and  the  fore  finger,  till  the  temperature  be  the 
same  as  that  of  the  skin  ;  then  separate  the  thumb  and 
finger  suddenly  ;  if  the  boiling  be  not  completed,  no  thread 
will  be  formed  between  the  two ;  if  there  be  a  filament,  the 
boiling  is  well  advanced ;  and  the  process  is  completed  as 
soon  as  the  filament  breaks  short,  and  the  upper  part,  hav- 
ing the  semi-transparency  of  horn,  curls  itfself  into  a  spiral. 
This  manner  of  trying  the  sirup  is  known  by  the  name 
proving. 

2.  The  second  mode  of  judging  of  the  completion  of 
the  process,  is  by  observing  the  time  when  the  sirup  ceases 


334  Cii'YMISTRY    APPLIED    TO    AGRICULTURE. 

to  moisten  the  sides  of  the  boiler,  and  then  blowing  forci- 
bly into  a  skimmer  which  has  just  been  immersed  in  it ;  if 
bubbles  escape  through  the  holes  of  the  skimmer  which 
ascend  into  the  air  in  the  same  manner  as  soap  bubbles  do, 
the  liquor  is  considered  to  be  sufficiently  boiled ;  the  fire  is 
therefore  immediately  extinguished,  and  the  sirup  is  a  few 
minutes  after  conveyed  to  a  great  copper  boiler,  which  is 
called  the  cooler. 

The  cooler  is  placed  in  an  apartment  of  the  manufac- 
tory near  the  boilers ;  its  capacity  should  be  such  as  to  al- 
low of  its  receiving  the  product  of  the  four  successive 
boilings.  The  cooling  which  the  sirup  experiences  in  this 
vessel,  quickly  produces  crystallization ;  the  crystals  form 
first  at  the  bottom,  where  they  collect  in  a  thick  bed,  hav- 
ing, however,  no  union  of  particles.  Gradually  the  sides 
become  covered  with  solid  crystals,  and  at  length  there  is 
formed  upon  the  surface  a  crust  of  sugar  which  thickens 
insensibly.  At  this  time  the  contents  of  the  cooler  are 
taken  out  to  fill  the  moulds  in  which  the  process  of  crys- 
tallization is  to  be  completed.* 

The  contents  of  the  cooler  are  first  thoroughly  stirred 
and  mixed,  and  then  thrown  gradually  into  the  moulds,  a 
portion  being  put  into  each  in  turn,  so  as  to  fill  them  all 
equally  :  an  interval  of  an  inch  is  left  between  the  surface 
of  the  sirup  and  the  top  of  the  mould. 

Crystallization  is  hastened  by  carrying  the  moulds,  as  soon 
as  they  are  full,  into  the  coolest  apartment  of  the  manufac- 
tory.t 

*  The  moulds  used  in  this  operation  are  known  in  refineries  by  the 
name  of  grandes  bdtardes.  They  are  large  conical  vessels  of  baked 
earth,  with  a  small  opening  at  the  apex,  and  capable  of  containing 
about  100  pounds  of  the  evaporated  sirup.  The  different  sizes  are 
distinguished  in  the  manufactories  as  grandes  et  petites  bdtardes,  ac- 
cording to  their  different  capacities  ;  they  are  numbered  1,  2.3,  4,  &c. 
Moulds  made  of  resinous  wood  have  supplied  the  place  of  these  in 
some  manufactories  ;  this  change  was  proposed  by  M.  Mathieu  de 
Dombasle,  and  in  those  countries  where  wood  is  abundant,  it  is  a,  good 
one  in  point  of  economy. 

The  moulds  must  be  soaked  in  water,  and  then  drained,  before  the 
sirup  is  put  into  them  }  the  opening  at  the  point  is  stopped  vv-ith  old 
linen,  and  the  vessels  themselves  supported  against  the  walls  to  re- 
ceive the  liquor. 

t  The  sirup  arising  from  the  employment  of  10,000  pounds  of  beet 
roots,  if  the  operations  are  well  conducted,  will  fill  nine  grandes  bd- 
tardes, each  bdtarde  containing  from  85  to  90  pounds  of  evaporated 
sirup. 

When  the  different  boilings  are  made  slowly,  or  experience  any  in- 
terruption, the  moulds  are  partially  filled  from  the  cooler,  without 


EXTRACTION  OF  SUGAR  PROM  BEETS.       335 

Cooling  causes  the  formation  of  crystals  upon  the  sides 
of  the  moulds  and  the  surface  of  the  liquor.  As  soon  as 
this  crust  of  crystals  has  acquired  some  degree  of  consis- 
tency, it  must  be  broken  with  a  wooden  spatula,  and  the 
whole  contents  of  the  mould  carefully  stirred,  so  as  to  col- 
lect in  the  centre  the  crystals  that  have  formed  upon  the 
sides.  When  this  has  been  done,  the  crystallization  is  al- 
lowed to  go  on  undisturbed. 

Three  days  are  more  than  enough  for  the  formation  of 
all  the  crystals;*  the  plugs  that  close  the  points  of  the 
moulds  are  then  taken  out,  and  the  moulds  are  placed  in 
earthen  pots,  that  the  molasses  may  flow  from  them,  t 

The  crystals  will  be  deprived  of  the  molasses  which 
unites  them  in  about  eight  days ;  the  moulds  are  then  car- 
ried into  an  apartment  which,  by  means  of  a  stove,  is  kept 
constantly  heated  to*  18°  or  20°  of  Reaumur,  (=  72.5°  and 
77°  Fahr.)  and  there  placed  in  fresh  pots. 

.The  next  operation  is  that  of  leaching  the  contents  of 
the  moulds,  in  order  to  obtain  from  them  that  portion  of 
molasses  which  refused  to  flow  out.  For  this  purpose  the 
surface  of  the  loaves  is  carefully  broken  and  scraped  with 
the  blade  of  a  knife,  so  as  to  smooth  it,  and  then  there  is 
thrown  upon  each  one  about  half  a  pound  of  a  white  sirup, 
marking  from  27°  to  30°,  {z=z  specific  gravity  of  1.231  to 
1.261. f)  This  sirup  penetrates  into  the  loaves,  diluting 
and  carrying  off"  the  molasses,  which  is  tl^ree  or  four  de- 
grees more  concentrated  than  itself  If  the  concentration 
of  the  sirup  were  less,  it  would  dissolve  the  sugar ;  if  it 
were  more,  it  would  render  the  sugar  adhesive.     This  op- 

waitinfif  for  the  last  product ;  otherwise  crystallization  would  be  com- 
pleted in  the  cooler,  and  all  the  contents  of  it  would  form  a  mass 
which  could  not  be  poured  into  the  moulds  to  extract  from  it  the  mo- 


*  The  operation  may  be  known  to  be  ffood, — 

1.  When  the  surface  of  the  crystallized  mass  is  dry,  so  that,  in  pass- 
ing the  hand  over  it,  neither  moisture  nor  adhesiveness  is  perceived. 

2.  When  the  crust  settles  and  breaks  in  the  centre  :  in  this  case  the 
refiners  say  the  sugar  makes  a  fountain. 

3.  The  yellow  color  of  the  crystals  is  generally  a  good  indication, 
but  in  the  case  of  beet  sugar  it  is  unimportant,  because  the  color  may 
have  been  blackened  by  tne  animal  charcoal  employed  when  the  fil 
tration  of  the  clarified  liquor  has  not  been  carefully  executed ;  and 
this  color  is  easily  made  to  disappear  by  clarification  and  refinement. 

t  These  pots  should  be  large  enough  to  contain  five  or  six  gallong 
of  liquor. 
t  This  sirup  is  only  a  portion  of  that  which  is  prepared  for  boiling. 


336  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

eration  is  renewed  two  or  three  times  at  intervals  of  two 
days. 

Wlien  the  loaves  have  remained  a  month  in  the  stove- 
room,  they  can  be  taken  out  of  the  moulds ;  they  are  then 
found  to  be  dry  and  entirely  deprived  of  molasses,  and  are 
piled  up  in  the  store-house,  where  they  are  kept  to  be  re- 
fined. 


ARTICLE  VII. 

"   On  Boiling  the  Molasses  and  Leaching  Sirups. 

I  MIX  the  molasses  obtained  from  the  brown  sugar  with 
the  sirups  which  have  been  filtrated  through  the  loaves, 
and  proceed  to  boil  the  mixture.  The  molasses  marks  23° 
or  24°,  (r=  specific  gravity  of  1.190  to  1.199,)  the  sirup  21° 
or  22°,  (—  1.171  to  1.180,)  and  the  mixture  22°  or  23°, 
(=  1.180  to  1.190.)  I  throw  from  32  to  35  gallons  of  this 
mixture  into  the  boiler,  and  when  the  heat  approaches  to 
ebullition,  I  add  about  one  pound  of  animal  charcoal, 
which  I  mix  carefully  with  the  liquor. 

The  boiling  of  this  liquor  is  more  difficult  than  that  of 
the  sirup  which  produces  the  brown  sugar,  but  with  care 
and  patience  it  may  be  done  to  very  good  advantage.  This 
liquor  yields  at  least  one  sixth  of  the  quantity  of  sugar  that 
has  been  procured  by  the  first  operation ;  this  product  is 
sufficiently  important  to  render  it  advisable  to  boil  down  the 
molasses,  instead  of  disposing  of  it,  as  is  almost  everywhere 
done,  for  distillation. 

If  the  molasses  procured  from  beets  was  of  the  same 
quality  as  that  obtained  from  the  sugar  cane,  it  could  be 
sold  with  advantage,  but  it  has  a  bitter  taste  which  renders 
it  unsalable  ;  it  is  best  then  to  exhaust  it  of  crystallizable 
matter,  and  to  subject  the  remainder  to  distillation.  The 
difference  in  the  quantity  of  alcohol  obtained  from  the  two 
kinds  of  molasses  is  almost  nothing. 

Instead  of  depositing  the  product  of  this  last  boiling  in 
moulds,  I  throw  it,  from  day  to  day,  into  a  hogshead  open 
at  one  end,  and  thus  gradually  fill  the  cask  ;  the  sugar 
crystallizes  wonderfully  in  these  vessels,  so  that  they  be- 
come half  full  of  it. 


REFINING    BEET   SUGAR.  337 

When  this  sugar,  which  I  call  molasses  sugar,  to  distin- 
guish it  from  the  brown  sugar  of  the  first  boiling,  is  to  be 
refined,  the  molasses  which  lies  upon  the  top  is  dipped 
out,  and  the  rest  is  made  to  flow  out  through  small  gimlet 
holes  bored  in  the  bottom  and  around  the  circumference 
of  the  cask. 

The  sugar,  when  deprived  of  all  the  molasses  which  can 
be  made  to  flow  from  it,  still  forms  only  an  adhesive  paste, 
which  can  scarcely  be  refined ;  I  therefore  put  this  paste 
into  bags  of  coarse,  strong  cloth,  and  subject  it  to  a  strong 
compression.  The  sugar  thus  freed  from  molasses  is  very 
dark  colored,  but  the  quality  of  it  is  excellent,  and  it  is  as 
easily  refined  as  the  best  brown  sugar. 

When  the  brown  sugar  boilings  turn  badly^  and  crystal- 
lization in  the  moulds  is  imperfect,  and,  in  a  word,  at  all 
times  when  sugar  is  ropy,  and  parts  but  imperfectly  with  its 
molasses,  it  is  necessary  to  subject  it  to  the  action  of  the 
press  before  attempting  to  refine  it ;  as  soon  as  it  has  in 
this  way  been  freed  from  all  its  molasses,  it  may  be  refined 
without  any  difficulty.* 


SECTION  III. 

On  the  Refining  of  Sugar  obtained  from  Beet  Roots. 

When  the  sugar  is  dry,  the  refining  of  it  is  easily  per- 
formed ;  all  possible  pains  then  should  be  taken  in  the  pre- 
ceding operations  to  free  it  from  all  its  molasses. 

All  the  operations  of  refining  may  be  brought  under  two 
heads,  clarification  in  the  boiler,  and  whitening  in  the 
moulds. 

To  refine  sugar  well,  it  is  better  not  to  operate  upon  too 

*  In  most  of  the  beet  sugar  manufactories  they  have  adopted  the 
swinging  boilers  for  preparing  their  sirups ;  concentration  is  per- 
formed speedily  in  these,  and  they  hare  the  advantage  of  being  emp*- 
tied  in  a  moment ;  but  they  are  usefiil  only  when  the  operation  ii 
performed  upon  dry  sugars,  like  the  American,  which  contain  but  lit« 
tie  molasses.  Our  beet  sugar  is  never  so  well  drained  as  the  imported 
sugars  are,  and  requires  much  more  care  in  the  boiling.  These  boil- 
ers appear  to  me  more  apt  to  cause  the  burning  of  the  sugar  than  th* 
old  kind,  and  I  therefore  give  the  preference  to  the  latter. 
29 


338  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

large  quantities.  I  have  always  observed  that  when  I  sub- 
jected to  the  same  refining  process  2000  or  3000  lbs.  of 
sugar,  the  last  boilings  were  ropy,  and  each  operation  less 
perfect  than  when  performed  upon  400  kilogrammes  (about 
890  lbs.)  at  one  time:  it  is  upon  this  last  quantity  that  I 
shall  found  my  calculations.* 


ARTICLE   I. 

On  Clarification.  - 

A  BOILER  four  or  five  feet  in  diameter  and  twenty-eight 
inches  in  depth  is  two  thirds  filled  with  water,  to  which 
lime-water  enough  to  fill  the  boiler  is  added ;  in  this  mix- 
ture is  dissolved  at  a  low  heat  400  kilogrammes  of  brown 
sugar. 

The  solution  must  not  mark  more  than  32°  (=  1.286) 
of  concentration  ;  if  it  stands  higher,  it  must  be  weakened, 
if  lower,  more  sugar  must  be  added.  This  state  of  con- 
centration belongs  only  to  solutions  of  dry  sugar ;  those 
of  damp  sugar  must  be  reduced  to  30°  or  25°,  (=:  1.261 
to  1.210,)  otherwise  it  will  be  almost  impossible  to  filtrate 
them. 

The  solution  is  then  heated  to  ebullition.  When  the  tenj- 
perature  reaches  65°  (=  178^°  Fahr.)  fifteen  kilogrammes 
(32f  lbs.)  of  animal  charcoal  are  added  to  it;  the  mixture 
is  then  carefully  stirred  and  mixed  with  a  wooden  spatula; 
after  allowing  it  to  boil  an  hour,  the  fire  is  extinguished. t 
The  boiling  liquor  is  freed  from  the  charcoal  by  filtration 
through  a  coarse  cloth,  and  when  the  heat  has  fallen  to 
40°,  (122°  Fahr.,)  the  whites  of  forty  eggs  beaten  and 
diluted  with  several  quarts  of  water  are  thrown  into  the 

*  I  have  never  been  able  to  assign  a  reason  for  this  difference,  but 
it  actually  exists ;  perhaps  it  arises  from  my  not  being  able  to  com- 
plete ray  boilings  in  one  day,  and  the  clarified  sirups  having  become 
changed  in  the  boiler ;  or  perhaps  a  large  quantity  of  sirup  may  be 
more  difficult  to  manage  than  a  small  one,  though  the  ingredients  be 
combined  in  the  same  proportions. 

t  The  quantity  of  animal  charcoal  added  ought  to  vary  according 
to  the  quality  of  the  sugar ;  that  which  is  dry  requiring  a  less  portion 
than  that  which  is  wet. 


REFINING    BEET    SUGAR.  339 

lx)iler.*  The  liquor  is  then  carefully  stirred,  and  is  kept 
constantly  in  motion  till  the  temperature  rises  to  70°, 
(=z  180°  Fahr.,)  when  stirring  is  omitted,  and  the  heat 
raised  to  the  boiling  point. 

As  soon  as  the  first  bubble  appears  upon  the  surface,  the 
firs  is  extinguished ;  a  thick  coat  of  scum  forms  upon  the 
surface  of  the  liquor,  and  is  removed  at  the  end  of  three 
quarters  of  an  hour. 

The  liquor  is  filtered  through  a  coarse,  thick,  rough  cloth  : 
if  the  first  portion  that  passes  through  be  not  perfectly  clear, 
it  is  to  be  thrown  again  upon  the  filter,  and  this  operation  is 
repeated  till  the  liquor  appears  completely  limpid  and  free 
from  any  floating  particles.  As  soon  as  the  liquor  is  perfect- 
ly clear,  it  is  boiled ;  five  or  six  boilings  being  formed  with 
the  product  of  the  clarification. 

The  several  boilings  are  thrown  into  the  cooler  as  fast 
as  they  are  completed,  and  from  thence  into  the  moulds 
four,  which  can  contain  5^  gallons  each.  These  opera- 
tions are  conducted  in  the  same  manner  as  those  which  I 
have  described  in  speaking  of  brown  sugar,  but  with  this 
diflference,  that  the  sugar  contained  in  the  moulds  is  stirred 
and  moved  at  two  different  times  before  it  is  taken  in  the 
mass.  ^ 

After  three  days  the  moulds  are  placed  upon  the  pots 
into  which  the  molasses  drains,  and  at  the  end  of  eight 
more,  they  are  removed  to  the  second  pots,  where  the 
whitening  is  to  be  performed. 


ARTICLE    IL 

On  Whitening  Sugar. 

The  clarified  sugar  is  dry,  of  a  yellow  color,  varying 
considerably  in  the  depth  of  its  hue;  the  taste  is  mild 
and  sweet.     The  process  of  bleaching  removes  from  it  the 

*  I  have  noticed  tliat  the  whites  of  eggs  coagulate  at  a  degree  of 
heat  between  30'-^  and  35°  of  Reaumur,  (=  122P  and  133^°  Fahr.) 
At  that  degree,  I  have  proceeded  to  clarification.  In  some  man- 
ufactories I  have  observed  that  the  whites  of  eggs  were  added  at 
the  moment  of  ebullition ;  but  in  this  case  they  are  immediately 
coagulated,  and  the  clarification  being  only  partial,  the  sugar  comeB 


340  CHTMISTRY    APPLIED  TO    AGRICULTURE. 

small  quantity  of  sirup  with  which  it  is  impregnated ;  it 
can  be  effected  in  three  ways,  namely,  by  the  use  of  clay, 
of  alcohol,  and  of  the  sirups ;  the  first  of  these  is  the  one 
generally  employed  in  the  refineries. 

When  sugar  is  to  be  clayed,  a  hogshead  unheaded  at 
one  end  and  furnished  with  a  row  of  stop-cocks  placed  one 
above  the  other  from  top  to  bottom,  is  partly  filled  with 
white  clay,  upon  which  water  is  poured  till  the  cask  is  full  ; 
the  clay  is  then  carefully  stirred,  so  that  every  portion  of 
it  may  be  well  washed.  This  operation  is  repeated  several 
times,  the  water  of  the  washings  being  drawn  off  as  soon 
as  the  clay  settles,  and  a  fresh  quantity  turned  in,  which 
is  stirred  in  the  same  manner.  The  washing  is  continued 
till  the  water  no  longer  appears  charged  with  any  foreign 
substances,  when  the  water  is  allowed  to  remain  undis- 
turbed upon  the  clay  till  this  becomes  thoroughly  divided^ 
so  that  upon  handling  it  no  lumps  can  be  found.  When 
the  clay  is  found  to  be  in  this  state,  all  the  water  is  drawn 
off,  and  the  clay  suffered  to  dry  gradually,  till  it  acquires 
such  a  degree  of  consistency  as  not  to  flow  when  placed 
upon  a  smooth  and  slightly  inclined  .board :  it  is  now 
considered  ready  for  use. 

Before  placing  the  prepared  clay  upon  the  sugar  con- 
tained in  the  moulds,  the  surface  of  the  loaves  is  carefully 
scraped,  so  as  to  remove  one  layer  of  the  sugar,  which  is 
replaced  by  a  portion  of  very  white  powdered  sugar ;  this 
is  piled  up  and  smoothed  very  nicely,  and  then  covered 
over  with  a  layer  of  clay  thrown  on  with  a  spoon.  The 
water  contained  in  the  clay  passes  gradually  into  the  layer 
of  white  sugar,  which  it  dissolves,  forming  a  sirup  which 
penetrates  into  the  loaves,  deprives  the  sugar  of  its  color, 
and  passes  out  at  the  point  of  the  mould. 

The  clay,  being  thus  gradually  deprived  of  water,  shrinks 
and  dries,  and  is  then  removed  and  thrown  into  the  cask  to 
be  made  use  of  in  new  operations. 

The  upper  part  of  the  loaves  is  rendered  white  by  this 
first  operation ;  but  when  the  liquid  which  flows  from  the 
opening  in  the  point  of  the  mould  is  colored,  a  second 
claying  is  performed ;  in  this,  however,  the  clay  alone  is 
used,  the  intermediate  layer  of  sugar  being  dispensed  with. 

•ut  brownish,  and  they  are  then  to  be  redissolved  three  or  four  times 
before  they  attain  the  desired  degree  of  whiteness ;  this  occasions 
much  labor  and  expense,  together  with  a  great  loss  of  sugar. 


REFINING    BEET    SUGAR.  341 

The  number  of  clayings  to  be  employed,  depends  upon 
the  quantity  of  coloring  matter  contained  in  the  sugar  ; 
two  are  usually  enough  to  render  sugar  merchantable  ; 
but  in  order  that  the  sirup  may  flow  off  free  from  any  tinge 
of  yellow,  three  must  be  employed. 

When  the  operation  of  claying  is  completed,  the  loaves 
are  placed  upon  their  bases,  that  the  white  sirup  by  which 
the  points  are  softened  may  diffuse  itself  through  the  mass. 

At  the  end  of  eight  or  ten  days  the  loaves  are  taken  out 
of  the  moulds  and  placed  in  a  stove-room,  in  which  they  are 
dried. 

The  method  of  whitening  by  clay  is  certain,  but  it 
possesses  the  great  fault  of  converting  into  sirup  nearly  ^ 
of  the  sugar  operated  upon  ;  and  if  the  sugar  is  adhesive,  or 
the  grains  of  it  very  fine,  the  quantity  of  sirup  formed  is 
still  more  considerable.  Whenever  I  have  worked  upon 
sugars  of  this  description,  I  have  melted  them  over,  and 
freed  them  from  their  adhesiveness,  by  boiling  them  down 
with  a  quantity  of  animal  charcoal. 

Brown  sugar  made  from  beets,  when  refined,  generally 
yields  in  molasses  or  nonconverted  sirup*  between  ^  and  \ 
of  its  own  weight,  and  it  loses  by  claying  at  least  ^. 

The  sirups  which  are  produced  during  these  various 
operations,  are  usually  boiled  without  the  addition  of  any 
foreign  substance,  and  the  product  of  these  boilings  is 
thrown  from  the  cooler  into  the  demi-bdtardes,  where  they 
become  crystallized  ;  these  form  the  large  loaves  of  sugar, 
weighing  between  22  and  27  lbs.  known  in  commerce 
under  the  name  of  lomhs. 

It  has  been  attempted  to  substitute  the  method  of 
whitening  by  alcohol  for  that  by  claying  ;  this  process  is 
founded  upon  the  power  which  alcohol  possesses,  of  dis- 
solving the  coloring  principle  without  acting  upon  the 
sugar.  I  followed  this  mode  two  months,  making  use  of 
no  other  alcohol  than  what  I  procured  from  the  distillation 
of  my  molasses.  I  confined  myself  in  this  process  to 
leaching  the  loaves  of  sugar  contained  in  my  moulds  with 
alcohol  of  35'  (  =  sp.  gr.  0.852)  of  concentration  ; 
covering  the  moulds  over  so  as  to  prevent  loss  by  evapora- 


*  The  molasses  or  simp  which  flows  from  the  mould  when  it  is  put 
upon  the  earthen  jar  after  crystallization  is  called  nonconverted  sirup  ; 
that  which  is  procured  by  claying,  converted  sirup;  the  last  is  purer, 
lighter  colored,  and  better  tasted  than  the  first. 

29* 


343  CUTMISTKY    APPLIED    TO    AGRICULTURE, 

tion,  and  renewing'  the  alcohol  till  the  liquor  passed  off 
perfectly  clear  from  the  point  of  the  mould  ;  this  alcohol 
I  redistilled,,  to  employ  in  new  operations. 

I  abandoned  this  method  of  bleaching  sugar  for  the  fol- 
lowing reasons. 

1.  Notwithstanding  all  the  precautions  I  took,  I  lost  half 
a  kilogramme  (a  little  more  than  a  pound)  of  alcohol  for 
each  loaf  of  ten  pounds'  weight. 

2.  The  loaves  of  sugar,  though  well  dried  in  the  stove^ 
always  preserved  a  slight  odor,  which  became  more  sensi- 
ble after  their  having  been  confined  in  the  papers  and 
transported. 

3.  The  price  of  alcohol  of  this  degree  of  concentration, 
rendered  the  refining  by  alcohol  as  expensive  as  that  of 
clay. 

Some  very  skilful  chymists  propose  to  supply  the  use 
of  clay  by  that  of  sirup  ;  theory  is  in  favor  of  this  method, 
but  experiment  contradicts  it. 

In  the  first  place,  in  order  that  the  sirup  may  be  em- 
ployed with  success,  it  is  necessary  that  it  should  be  white, 
and  of  course  that  it  should  be  made  by  saturating  water 
with  very  white  sugar.  The  water  which  is  disengaged 
from  the  clay  produces  a  sirup  in  passing  through  the 
layer  of  sugar  with  which  the  loaves  are  covered ;  there 
is,  therefore,  no  advantage  to  be  derived  from  the  use  of 
sirup  on  account  of  its  containing  sugar,  and  the  process 
is  less  economical  than  claying,  inasmuch  as  both  time 
and  fuel  *  are  required  for  making  the  sirup,  whilst  in 
claying  it  is  produced  by  the  process  itself. 

However,  as  the  theory  is  seducing,  I  tried  this  method, 
and  the  following  statement  exhibits  the  results. 

I  prepared  a  quantity  of  sirup  at  30°  t  (  :=  1.261)  of 
concentration,  which  I  poured  upon  the  smoothed  surface 
of  the  loaves  till  they  were  covered  with  it ;  the  following 
day  the  sirup  had  penetrated  into  the  mass,  which  was 
sensibly  whitened  by  it.  I  repeated  the  operation  at  inter- 
vals of  four  hours,  till  the  sirup  passed  off  through  the 
point  of  the  mould  clear ;  this  did  not  take  place  till  the 

*  I  say  fuel,  because  water  will  not  dissolve  so  much  sugar  by  re- 
maining upon  it  at  the  temperature  of  the  atmosphere,  but  that  it  will 
take  up  stlU  more  in  filtrating  through  it ;  so  as  to  increase  in  con- 
centration\3''  or  4°. 

t:  This  is  the  point  to  which  it  is  necessary  to  caxry  it,  that  it  may 
not  dissolve  the  sugar  when  cold. 


REFINING    BEET    SUGAR.  343 

end  of  twenty  days,  at  which  time  the  bleaching  of  the 
greater  part  of  the  loaves  was  completed.  J  continued 
the  operation  upon  the  others  from  twelve  to  twenty  days, 
removing  successively  those  that  were  finished. 

When  I  came  to  take  these  loaves  from  the  moulds,  they 
came  out  in  fragments ;  the  sugar  was  moist  and  without 
consistency  ;  it  was  impossible  to  dry  it,  and  I  was  obliged 
to  melt  it  over  and  make  double-refined  sugar  of  it.  I  re- 
peated the  operation  of  bleaching  with  sirup  several  times, 
and  aKvays  obtained  the  same  results. 

It  is  evident  that  the  sirup  applied  in  this  manner  inter- 
poses itself  between  the  molecules  of  the  sugar,  and  there 
remains ;  whilst  in  the  process  of  claying,  the  sirup,  being 
formed  gradually,  passes  through  it  by  insensible  filtration, 
imbibing  the  coloring  matter,  which  it  at  length  carries  off. 
I  moreover  found  that  it  required  twice  as  much  sugar 
to  form  the  sirup  as  was  needed  in  the  usual  method  of 
claying. 

The  numerous  experiments  which  I  have  been  in  the 
way  of  making  during  a  dozen  years,  have  induced  rae  to 
adopt  a  process  which  appears  to  me  to  be  more  advan- 
tageous than  either  of  those  of  which  I  have  just  spoken. 
I  cut  out  of  the  coarse  cloth  called  calmuck,  round  pieces 
of  the  same  size  as  the  bases  of  the  loaves  ;  these  I  soak 
in  water  and  afterwards  wring  ;  I  then  apply  them  care- 
fully to  the  bases  of  the  loaves,  which  have  been  previously 
scraped  and  smoothed  with  the  blade  of  a  knife,  or  a  small 
trowel.  In  twenty-four  hours'  time  the  surfaces  of  the 
loaves  are  bleached.  I  then  pour  upon  the  cloth  about 
half  a  pound  of  the  converted  sirup  of  the  last  claying; 
the  sirup  gradually  penetrates  the  cloth,  and  filtrates 
through  the  loaves,  from  which  it  removes  all  the  coloring 
matter. 

As  soon  as  the  sirup  has  passed  through  the  cloth  into 
the  sugar,  I  moisten  the  cloth  by  sprinkling  it  with  drops 
of  water,  and  the  next  day  I  throw  upon  it  the  same  quan- 
tity of  converted  sh-up* 

This  first  operation  is  completed  in  five  or  six  days, 
after  which  the  sirup  is  left  to  flow  during  four  or  five  days. 
By  these  leachings  the  loaves  are  perfectly  bleached  to 
the  depth  of  four  or  five  inches,  but  they  are  still  a  little 

*  I  here  suppose  that  I  operate  upon  moulds  of  fimr,  the  loave* 
from  which  weigh  from  11  to  14  lbs. 


344  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

colored  below ;  I  complete  the  bleaching  by  a  slight  clay- 
ing, applying  the  earth  immediately  to  the  surface  of  the 
loaves  without  any  intermediate  layer  of  sugar. 

I  find  that  bleaching  is  performed  more  speedily  and 
with  less  labor  in  this  way  ;  the  evils  arising  from  the  use 
of  sirup  alone  are  obviated,  and  but  a  small  portion  of 
sugar  already  bleached  is  dissolved. 

In  order  to  appreciate  all  the  advantages  arising  from 
well-conducted  operations,  it  is  necessary  that  one  should 
know  the  change  produced  in  sugar  by  repeated  meltings  ; 
it  is  brought  first  to  a  point  when  it  will  no  longer  crystal- 
lize, and  afterwards  to  the  state  of  molasses.  Sugar  which 
has  been  three  or  four  times  boiled  over,  will  still  crystal- 
lize upon  the  sides  of  the  moulds,  but  the  middle  of  the 
loaf  will  be  only  a  uniform,  thick,  white  mass,  destitute  of 
the  agreeable  taste  of  sugar ;  this  substance,  if  melted,  does 
not  again  become  solid,  but  remains  in  the  state  of  mo- 
lasses. 

I  ought  to  mention,  that  in  the  various  operations  that 
are  performed  upon  sugar,  the  nature  of  the  substance  is 
often  made  to  undergo  a  series  of  changes  or  a  succession  of 
degenerations  equally  constant  and  regular. 

I  have  just  mentioned  that  when  sugar  is  made  to  re- 
pass two  or  three  times  through  the  boiler,  it  is  rendered 
uncrystallizable,  and  the  middle  of  the  loaf  is  found  to 
consist  of  a  uniform  mass  of  the  consistency  of  butter, 
not  possessing  the  agreeable  flavor  of  crystallized  sugar. 
This  mass,  dissolved  in  water  and  concentrated  by  heat, 
is  reduced  to  molasses;  and  when  the  evaporation  and 
clarification  of  the  juice  of  beets  is  prolonged  beyond  a 
certain  time,  nearly  all  the  sugar  is  reduced  to  molasses, 
and  the  boiling  is  rendered  long  and  difficult ;  when  this 
is  the  case,  the  sirup  throws  up  an  abundance  of  adhe- 
sive white  foam,  which,  when  removed  with  a  skimmer, 
thickens  and  presents  all  the  characteristics  of  vegetable 
wax.  The  experience  of  twelve  years  has  uniformly  fur- 
nished me  with  these  results. 

I  am  thoroughly  convinced  that  these  alterations  would 
be  avoided  by  evaporating  the  sirup  in  a  vacuum  ;  it  has 
even  occurred  to  me  that  the  animal  charcoal  produced 
good  effects  only  by  its  opposing  the  action  of  the  oxygen 
of  the  atmosphere  upon  the  sugar,  since  nearly  the  same 
results  are  obtained  by  the  use  of  butter  and  other  oily 
substances  susceptible  of  extreme  division.     The  secret  of 


DISTILLATION    OF    BEET    MOLASSES.  345 

causing  this  decomposition  to  retrace  its  steps,  stUl  remains 
to  be  discovered  ;   I  have  essayed  it  without  success. 


SECTION   IV. 

On  THE  Distillation  of  Beet  Molasses. 

The  molasses  from  beets,  when  exhausted  of  its  sugar, 
has  not  the  pleasant  taste  of  that  furnished  by  the  sugar- 
cane, but  retains  a  bitter  taste  which  renders  it  fit  only  for 
distillation. 

The  product  in  molasses  is  as  great  as  that  in  sugar  : 
each  of  the  grandes-bdtardes  in  which  the  product  of  the 
first  boiling  is  crystallized,  yields  40  lbs.  of  molasses,  and 
45  lbs.  of  brown  cr  unrefined  sugar  :  these  40  lbs.  of  mo- 
lasses, boiled  over,  produce  6  lbs.  of  sugar  and  34  lbs.  of 
molasses ;  thus  from  two  boilings  are  obtained  34  lbs  of 
molasses,  and  51  lbs.  of  brown  sugar. 

As  this  sugar  is  not  pure,  it  is  necessary,  in  order  to  re- 
fine it,  that  it  should  be  melted  down,  crystallized,  and 
whitened.  By  these  operations  some  molasses  and  some 
sirup  is  extracted  from  it.  The  molasses  flows  from  the 
moulds  when  they  are  placed  upon  the  jars,  after  the  brown 
sugar  has  crystallized  ;  the  sirup  is  formed  during  the  pro- 
cess of  claying  ;  this  is  boiled  over  to  obtain  the  sugar 
dissolved  in  it,  and  the  molasses  remaining  is  mixed  with 
that  in  the  jars  to  be  distilled. 

The  weight  of  molasses  obtained  by  these  various  ope- 
rations is  nearly  equal  to  that  of  the  brown  sugar. 

Supposing  that  I  wish  to  produce  the  fermentation  of 
445  lbs.*  of  molasses,  to  prepare  it  for  distillation  ;  I  pro- 
ceed in  the  following  manner.  I  throw  the  whole  quantity 
of  molasses  into  a  vat,  and  there  add  to  it  such  a  quantity 
of  water  as  shall  cause  the  liquor  to  mark  7°  or  8°  (=  1.052 
to  1.060)  of  concentration,  I  stir  the  mixture  with  the 
greatest  care,  so  as  to  unite  the  two  fluids  thoroughly.  The 
vat  is  situated  in  an  apartment  of  the  manufactory,  where 
the  temperature  is,  by  means  of  a  stove,  kept  constantly 

*  I  usually  operate  upon  890  lbs.  The  vats  in  which  fermentation 
is  carried  on  contain  581  gallons. 


346  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

at  20°  or  22°,  (probably  of  Reaumur,)  (=  IT  and  88^° 
Fahr.)  and  I  take  care  that  the  liquor  be  raised  to  15°  or 
16°,  (=  specific  gravity  of  1.116  to  1.125,)  before  the  yeast 
is  added  to  it. 

To  make  the  leaven,  which  must  be  prepared  on  the 
morning  of  the  day  in  which  it  is  to  be  used,  I  form  25 
lbs.  of  rye  meal  into  a  paste  with  molasses,  and  then  dilute 
the  paste  with  boiling  water,  to  which  I  gradually  add  one 
quart  of  pure  molasses,  kneading  the  mass  thoroughly  till 
it  is  of  the  consistency  of  porridge  :  the  heat  of  it  in  this 
state  should  be  20°  or  25°,  {z=.lT  to  88°  Fahr.)  When 
this  leaven  is  formed  for  a  first  operation,  a  little  beer  yeast 
or  leaven  of  wheat  flour  should  be  added  to  it.  The  bucket 
is  covered  over,  and  set  into  a  place  sufficiently  warm  to 
produce  fermentation  :  the  yeast  soon  begins  to  swell,  and 
rises  seven  or  eight  inches  in  the  bucket ;  at  the  end  of 
twelve  or  fourteen  hours  it  is  ready  for  use.*  The  yeast 
is  thrown  by  small  portions  at  a  time  into  the  vat,  the 
liquor  in  which  is  stirred  during  the  whole  time. 

Fermentation  commences  in  the  course  of  two  or  three 
hours,  and  continues  two  or  three  days. 

The  concentration  of  the  liquid  is  gradually  diminished, 
and  at  the  end  of  the  operation  falls  to  2°t,  {=i  specific 
gravity  of  1.014.) 

The  next  process  is  that  of  distillation  :  the  liquor  is 
poured  into  the  boiler  of  the  alembic  through  a  cloth 
strainer,  by  which  all  the  meal  and  bran  contained  in  it 
are  separated ;  without  this  precaution,  the  liquor  would 
often  ascend  during  distillation  into  the  worm. 

When  c^stillation  is  carried  on  in  the  improved  alem- 
bics, tli/e  first  alcohol  which  passes  marks  36°  (=:  0.847) 
of  the  hydrometer  ;  it  becomes  gradually  weaker  till  it 
stands  at  only  10°  or  12°,  (=  specific  gravity  of  1.000  to 
0.987;)  the  operation  is  then  arrested.  The  mixture  of 
the  products  forms  spirit  marking  from  22°  to  25°  (zzz  spe- 
cific gravity  of  0.932  to  0.906.) 

The  after-taste  of  this  spirit  is  so  bitter  as  to  diminish 
its  value  in  commerce :   I  have  been  able  to  correct  this 

*  Before  making  use  of  this  yeast,  about  one  sixth  part  of  it  is 
poured  into  a  separate  vessel,  to  be  used  in  the  next  preparation  of 
yeast  that  may  be  needed ;  so  that  in  the  subsequent  operations  only 
20  lbs.  of  meal  are  required  instead  of  25  lbs. 

t  Those  substances  foreign  to  the  saccharine  principle  contained 
in  beets  do  not  ferment ;  they  therefore  prevent  the  degree  of  concen- 
tration from  being  less  than  2°. 


DISTILLATION    OP    BEET    MOLASSES.  347 

fault  by  mixing  about  2^  lbs.  of  animal  charcoal  with  the 
liquor  of  each  boiling ;  this  is  90  gallons  :  the  spirit  ob- 
tained by  this  process  differs  but  little  from  wine-brandy, 

r  redistil  nearly  all  the  spirit  over  a  naked  fire,  employing 
for  it  the  same  proportion  of  animal  charcoal,  and  convert 
it  into  alcohol  of  34°,  (=0.858.) 

The  sale  of  the  alcohol  is  more  easy  and  profitable  than 
that  of  the  spirit,  as  this  quality  of  alcohol  is  in  much  re- 
quest amongst  the  manufacturers  of  colors  for  dissolving 
their  resins. 

I  once  thought,  that  it  would  be  more  advantageous  to 
leach  the  mash  of  the  beets  in  order  to  mix  the  juice  thus 
obtained  with  the  molasses,  and  to  ferment  them  together, 
but  experience  has  undeceived  me  ;  the  juice  ferments,  and 
the  molasses  does  not  then  undergo  decomposition;  it  is 
found  in  the  boiler  unchanged.  I  have  found  the  same  re- 
sults to  be  produced,  when  I  have  mixed  the  must  of  grapes 
with  molasses. 

200  kilogrammes  (445^  lbs.)  yield  upon  distillation 
about  13  gallons  of  spirit  of  22°,  (=  0.932  ;)  these  13  gal- 
lons produce  6^  gallons  of  alcohol  at  34°.  The  expenses 
of  the  operation  may  be  calculated  thus  : 

One  man,  who  conducts  all  the  operations,  and  completes 
the  distillation  of  it  in  one  day,     .     1  franc  50  centimes. 
Ten  kilogrammes  of  rye,    ....     1 

Pit  coal, 3 

Animal  charcoal, 0  50 

Total,     6  francs  0  (=  $1.14.) 

The  conversion  of  this  spirit  into  alcohol  of  34°  costs  as 
follows : 

Day*s  wages,     ...     1  franc         50  centimes. 

Pit  coal,       ....     3 

Animal  charcoal,  .     .     0  60 


Total,  5  francs  0 

From  this  it  appears  that  the  profits  are  not  great,  but 
distillation  gives  an  actual  value  to  molasses  which  is  worth 
nothing. 


348  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

SECTION  V. 

On  the  Products  of  a  Beet  Sugar  Manufactory.* 

In  estimating  the  value  of  the  products  of  a  sugar  man- 
ufactory, I  will  suppose  that  10,000  lbs.  of  beet  roots  are 
operated  upon  each  day ;  however,  as  beets  cannot  be  em- 
ployed till  after  they  have  been  carefully  trimmed,  there 
is  perhaps  a  loss  of  ^  part  of  that  weight ;  thus,  in  order 
actually  to  work  upon  10,000  lbs.  of  beets,  it  is  necessary  to 
employ  12,000  lbs.  so  as  to  allow  for  this  loss. 

The  products  of  a  sugar  manufactory  are  of  two  kinds ; 
the  first  consists  of  the  sugar,  the  second  is  furnished  by 
the  molasses,  the  mash,  and  the  trimmings  of  the  beet 
roots. 


ARTICLE  I. 

Of  the  Product  in  Sugar. 

The  product  of  the  concentrated  sirup  obtained  from 
10,000  lbs.  of  trimmed  beets  will  fill  eight  moulds,  each 
of  which  will  contain  47  lbs.  of  good  brown  sugar;  this 

makes 376  lbs. 

The  molasses  obtained  from  the  moulds 
furnishes  ^  as  much  sugar  as  is  ob- 
tained by  the  first  operation,  equal  to  62§ 

Total,  438§  lbs. 
This  quantity  of  brown  sugar  will,  when  refined,  produce 
at  least  ^^nr  of  very  good   double  refined  sugar ;  and  -^ 
of  sugar  of  an  inferior  quality  obtained  from  the  molasses 
and  sirups  ;  the  whole  quantity  of  sugar  being  y^^^^. 

According  to  this,  the  average  quantity  obtained  by  an 
operation  skilfully  conducted  is, 

In  sugar  of  the  first  quality,     ....     187  lbs. 
In  sugar  of  the  second  quality,     ...       60 

Total,  244  lbs. 

•  In  the  estimate  which  follows,  I  have  always  valued  the  products 
at  the  lowest  rate,  and  the  expenses  at  the  highest. 


PRODUCTS    OP    A    BEET    SUGAR   MANUFACTORY.         349 

ARTICLE  11. 

On  the  Secondary  Products. 

The  operations  upon  10,000  lbs.  of  beets  per  day  pro- 
duce, 

In  mash, ^)511^  lbs. 

In  molasses,  about 280 

The  trimmings  of  10,000  lbs.     .     2,226 


ARTICLE  III. 
On  the  Value  of  the  Products* 

84  KLOgrammes  (187  lbs.)   of  good 

refined  sugar,  at  2  francs  5  centimes 

per  kilogramme, 210  francs  0 

30  kilogrammes  (60  lbs.)  of  middling 

sugar,  at  2  francs  25  centimes  per 

kilogramme, 67  50 

Total,  277  francs  50 
To  give  a  value  to  the  secondary  products  of  the  opera- 
tion upon  10,000  lbs.  of  beet  roots,  it  is  necessary  to  de- 
duce it  from  the  price  which  they  bear  in  commerce,  or 
from  that  of  the  articles,  the  places  of  which  they  supply. 

1.  I  have  estimated  the  weight  of  the  trimmings  of 
10,000  lbs.  of  beet  roots  to  be  2,000  lbs. ;  but  these  trim- 
mings contain  nearly  ^  their  weight  in  earth,  and  are  fit 
only  for  feeding  swine ;  they  will  supply  the  nourishment 
for  twenty-five  or  thirty  of  these  animals  during  the  time 
that  the  operations  upon  the  beets  are  continued.  The 
value  of  the  trimmings  may  be  fixed  at  two  francs  and  fifty 
centimes. 

2.  The  product  in  mash  is  far  more  valuable ;  this  sub- 
stance forms  excellent  food  for  animals,  especially  horned 
cattle  :  cows  and  sheep  that  are  fed  upon  it  give  large 
quantities  of  milk. 

The  mash  contains  about  ^^^  of  the  nutritive  principle 
of  the  beets,  since  only  water  and  about  f^  of  sugar  or 
molasses  can  be  extracted  from  them. 
30 


350 


CHYMISTRY    APPLIED    TO    AGRICULTURE. 


This  article  of  food  does  not  produce  the  same  evil  as 
dry  fodder,  which  lessens  the  quantity  of  milk,  and  ob- 
structs the  intestines  of  neat  cattle,  neither  does  it  pro- 
duce the  purging  and  leanness,  which  are  often  occasioned 
by  the  use  of  green  and  watery  herbage. 

The  mash  is  prepared  in  winter,,  and  it  is  at  that  season 
that  animals  experience  the  greatest  need  of  this  kind  of 
food. 

One  kilogramme  of  this  mash  and  one  quarter  of  a  kilo- 
gramme of  dry  fodder,  is  more  than  enough  to  feed  a 
merino  sheep  that  gives  suck. 

If  the  price  of  the  mash  is  estimated  at  only  twelve  francs 
per  1000  lbs.,  the  value  of  the  mash  each  day  will  be  thirty 
francs. 

3.  As  the  molasses  has  no  other  value  than  that  which  it 
receives  from  distillation,  it  can  be  estimated  only  by  the 
products  of  this  operation ;  and  as  the  price  of  spirit  varies 
greatly,  it  is  impossible  to  settle  it.* 

I  do  not  think  that  the  value  of  the  molasses  should  be 
estimated  higher  than  nine  francs  for  50  kilogrammes  ; 
10,000  lbs.  of  beet  roots  produce  130  kilogrammes  ;  this 
is  then  an  amount  of  twelve  francs  per  day. 

Table  of  the  Products  of  the  operations  upon  10,000  lbs. 
of  Beet  Roots  per  day. 


Nature  of  the  Products. 

Weight. 

Value. 

1.  Refin'd  (1st  qual. 
sugar,    (  2d  qual. 

2.  Trimmings 

3.  Mash 

4.  Molasses 

Total 

84  kilogrammes 
30     ...     . 

1,000     .... 

1,250     .... 
130     ...     . 

210  frs.    0  c. 
67  "    50 
2  ''    50 
30  " 
12  '* 

2,494  kilogrammes 

322  frs. 

Whilst  enumerating  the  products  of  beets,  I  have  neg- 
lected one,  which  is  however  of  some  importance  ;  it  is  the 
leaves.  As  soon  as  the  middle  of  August,  the  leaves  may 
be  trimmed  off  to  feed  animals ;  at  the   season  of  digging, 

*  Since  my  establishment  was  formed,  I  have  sold  alcohol  of  35° 
(=  specific  gravity  of  0.852)  at  various  prices  between,  160  francs  and 
500  francs  per  cask. 


EXPENSE    OF    A    BEET    SUGAR    MANUFACTORY.  351 

an  immense  number  of  cows  and  sheep  may  be  fed  for 
eight  or  ten  days  upon  the  leaves  and  necks  that  are  cut 
off  and  thrown  upon  the  ground. 


SECTION  VL 
On  the  Expense  of  a  Beet  Sugar  Manufactorit, 

It  is  not  enough  to  estimate  the  products  of  a  sugar 
manufactory,  in  order  to  know  whether  the  business  can  be 
carried  on  to  advantage;  a  valuation  of  the  expenses  must 
likewise  be  made :  in  this,  as  in  the  foregoing  part  of  my 
statement,  I  shall  give  only  the  results  of  my  own  experience. 

The  expense  of  the  necessary  accommodations  and  uten- 
fiils  required  for  operating  daily  upon  10,000  lbs.  of  beet 
roots  cannot  be  defrayed  witb  less  than  20,000  francs. 

If  a  permanent  stream  of  water  and  a  wine-press  can  be 
made  use  of,  the  expense  may  be  reduced  to  16,000  francs.* 

1.  The  principal  article  in  the  expenses  of  a  manufactory 
of  this  kind  is  the  cultivation  of  the  beets.  Estimating 
the  price  of  1,000  lbs.  at  ten  francs,  is  placing  it  at  a  rate 
by  which  the  manufacturer  will  escape  injury. t 

*  I  do  not  include  buildings,  since  such  as  are  necessary  for  thii 
manufacture  are  to  be  found  almost  every  where. 

t  If  the  proprietor  of  a  manufactory  should  cultivate  the  beets  him- 
self, sowing  his  fields  with  corn  immediately  after  digging  the  roots, 
the  expense  of  the  preparatory  ploughings  performed  in  the  winter 
and  spring,  and  that  of  the  manure  and  transportation,  would  be  borne 
entirely  by  the  crops  of  corn,  and  there  would  remain  to  the  charge 
of  the  beets,  which  form  an  intermediate  harvest,  only  the  cost  of  sow- 
ing, weeding,  digging,  and  transportation  ;  thus  the  price  of  these  will 
be  greatly  mminished. 

It  is  easy  to  estimate  upon  this  ground  the  cost  of  the  beets  to  a 
manufacturer  who  cultivates  them  himself :  I  will  here  give  the  esti- 
mate of  costs  for  a  single  acre. 

Purchase  of  six  pounds  of  seed         .         .         "6  francs. 

Sowing  the  same 12 

Two  weedings 22 

Digging 20 

Transportation 20 

Storing        .  3 

Rent  of  the  land 40 

Taxes 10 

Total,  133  franca. 
Estimating  the  mean  product  at  20,000  lbs.,  the  cost  to  the  farmer 


352  CHYMISTRY    APPLIED    TO   AGRICULTURE. 

Thus,  12,000  lbs.  of  roots  being  made  use  of  each  day, 
in  order  that  10,000  lbs.  may  be  prepared  for  the  rasp,  the 
cost  will  be 120  francs. 

2.  The  trimming  of  12,000  lbs.  at  the 
rate  of  60  centimes  per  1,000  lbs. 

of  trimmings, 7         20  c. 

3.  Wages  of  eight  women  employed  to 
tend  the  rasps,  carry  the  beets,  &,c. 
reckoned  at  60  centimes  per  day,  4         80 

4.  Hire  of  man  and  two  horses  for  the 
establishment,        7         25 

5.  Two  men  for  the  presses,      ...  2         50 

6.  Inspector  of  the  rasps  and  presses,  1         50 

7.  Two  men  to  the  boilers,        ...  2         50 

8.  50  kilogrammes  per  day  of  animal 
charcoal, 13 

9.  Value  of  coal  consumed,*    ...  25 

10.  Salary  of  the  head  refiner,    ...         5 

11.  Salary  of  a  second  refiner,    ...         2         25 

12.  Lighting  of  the  building,      ...         1         50 

Total,  192  frs.  50  c. 

This  list  comprises  only  the  expenses  of  a  day's  labor ; 
if  the  operations  should  be  continued  one  hundred  days, 
the  expenses  would  amount  to  19,250  francs. 

When  the  preparation  of  the  juice  and  the  manufactur- 
ing of  the  brown  sugar  are  completed,  all  the  work  people, 
excepting  the  two  refiners,  are  dismissed ;  these  are  enough 
for  carrying  on  the  operation  of  refining.  The  expenses 
attendant  upon  this  last  operation,  which  continues  till  au- 
tumn, are  as  follows  : 

1.  Wages  of  the  head  refiner,     .     .       1,000  francs. 

2.  Wages  of  the  second   refiner,     .  500 

3.  Wages  of  a  laborer,       ....  250 

4.  For  animal  charcoal,     ....  300 

of  1000  lbs.  is  6  francs,  65  centimes.  The  expense  of  labor  and  ma- 
nure are  borne  by  the  corn  which  is  sown  immediately  after  the  dig- 
ging of  the  beets ;  the  crops  of  corn  are  improved  by  interposing  the 
crop  of  beets  between  them,  as  the  earth  is  rendered  light,  and  the 
frequent  weedings  free  the  ground  from  all  injurious  plants. 

*  This  price  is  based  upon  the  situation  of  my  own  works  in  Tou- 
raine,  two  leagues  distant  from  the  mines  :  it  must  vary  with  the  dis- 
tance and  the  difficulty  of  transportation. 


EXPENSE  OF  A  BEET  SUGAR  MANUFACTORY.     353 

5.  For  pit  coal, 700 

6.  For  whites  of  eggs,        ....  100 

7.  For  pipe  clay,       50 

Total,  2,900  francs. 

To  these  expenses  must  be  added  the  following : 

1.  Interest  of  the  funds  employed  in 

furnishing  the  manufactory,      ....         1,200  francs. 

2.  For  repairing  and  replacing  uten- 
sils of  all  sorts, 1,500 

3.  For     purchasing    bags,    strainers, 

and  other  small  matters, 700 


3,400  francs. 
Thus  the  actual  amount  of  expenses  of  all 

kinds  attendant  upon  working  1,200,000 

lbs.  of  beets,  amounts  to 25,550  francs. 

I  have  already  proved  the  product  per  day 

to  be  322  francs ;  this  would  give,  for  one 

hundred  days  of  effective  labor,     .     .     .     32,200 


This  allows  to  the  manufactory  a  profit  of         6,650  frs. 

The  calculations  are  exact,  and  deduced  from  the  results 
of  a  well-conducted  process.  A  variation  from  them  can 
only  be  produced  by  local  situations.  ,  But  experienced 
agriculturists  will  perceive,  that  I  have  placed  certain 
expenses  at  the  highest  rate,  whilst  some  of  the  receipts 
are  estimated  at  the  lowest.  There  are  but  few  sections 
of  France,  where  pit  coal  is  as  dear  as  it  is  in  Touraine, 
where  my  establishment  is  situated.  There  would  be, 
almost  everywhere  else,  a  considerable  saving  in  this  arti- 
cle. I  have  rated  the  value  of  the  mash  only  at  12  francs 
per  1,000  pounds,  although  it  is  very  nearly  as  valuable 
for  feeding  animals  as  an  equal  weight  of  dry  fodder.  I 
have  estimated  the  price  of  the  roots  at  10  francs  per 
1000 ;  but  this  is  more  than  they  would  cost  a  landholder, 
especially  if  he  should  sow  corn  immediately  after  the 
beets  are  dug.  I  have  set  no  price  on  the  leaves  of  the 
beets,  and  yet  these  will  furnish  food  for  the  animals  of 
the  farm  from  the  middle  of  August  till  the  end  of  Octo- 
ber. 

But,  whatever  profits  this  manufacture  is  capable  of 
affording,  it  must  always  be  remembered  that  a  want  of  skill 
30* 


354  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

in  the  operations,  or  negligence  in  the  preservation  of  the 
roots,  must  occasion  some  losses  in  an  undertaking,  which, 
even  at  the  low  price  at  which  I  have  estimated  sugar, 
promises  sufficient  remuneration  in  the  hands  of  an  intelli- 
gent man. 


SECTION  VII. 
General   Considerations. 

From  twelve  years'  experience  I  have  learned,  in  the 
first  place,  that  the  sugar  extracted  from  beets  differs  from 
that  of  the  sugar-cane  neither  in  color,  taste,  nor  crystal- 
lization ;  and,  in  the  second  place,  that  the  manufacture 
of  this  kind  of  sugar  can  compete  advantageously  with  that 
of  the  sugar-cane,  when  the  price  of  this  last  is  in  com- 
merce one  franc  and  twenty  centimes  per  demi-kilogramrae 
(=r  18^  cents  per  pound.*) 

These  facts  being  established  and  acknowledged,  it  may 
be  asked  whether  the  manufacture  of  beet  sugar  would  be 
advantageous  to  agriculture. 

The  cultivation  of  beets  will  not  prevent  the  production 
of  a  single  kernel  of  wheat,  since  this  may  be  made  an  in- 
termediate crop,  and  the  sowing  of  it  commenced  as  soon 
as  the  beets  shall  be  dug.  The  crops  of  corn  are  better 
upon  these  lands  than  upon  others,  because  the  beets  have 
divided  and  loosened  the  earth,  and  the  weedings  have 
cleared  it  of  strange  plants. 

*  It  is  objected,  that  beet  sugar  of  bad  quality  is  thrown  into  the  mar- 
ket. I  do  not  contradict  the  fact ;  but  it  only  proves  that  the  sugar 
was  badly  made.  During  ten  years,  the  sugar  from  my  manufactory 
has  been  sold  at  the  same  price  as  that  from  the  sugar-cane  of  the 
same  degree  of  refinement ;  and  not  the  slightest  difference  between 
the  two  has  ever  been  perceived. 

It  is  said,  that  the  greater  part  of  the  establishments  of  this  kind 
have  been  given  up,  after  having  occasioned  loss  to  the  proprietors. 
This,  also,  is  a  fact  which  I  shall  not  dispute.  But  I  must  remark, 
that  this  new  branch  of  industry,  like  all  others,  requires  some  knowl- 
edge and  apprenticeship.  It  needs  to  be  conducted  by  men  accus- 
tomed to  similar  operations ;  and  it  is  not  at  all  surprising,  that  these 
have  not  been  everywhere  found. 

It  is  impossible  to  mention  any  kind  of  manufacture  amongSt  those 
tiiat  have  succeeded,  where  perfection  has  been  attained  at  once. 


GENERAL    CONSIDERATIONS.  355 

The  operations  upon  10,000  pounds  of  beets  per  day, 
place  at  the  disposal  of  an  agriculturist  about  1250  kilo- 
grammes (=  1^  tons)  of  mash,  which  is  the  best  kind  of 
food  for  horned  cattle. 

The  working  of  the  beets  'being  performed  in  winter, 
furnishes  employment  to  the  men  and  cattle  of  a  farm,  at 
a  season  when  they  are  too  often  condemned  to  idleness. 

Finally,  if  the  manufacture  of  sugar  from  beets  should 
be  carried  to  such  an  extent  as  to  furnish  a  supply  for  all 
France,  agriculture  would  receive  from  it  the  value  of  more 
than  80,000,000  francs  per  annum. 

The  prosperity  of  an  establishment  of  this  kind,  depends 
upon  its  being  connected  with  rural  labors.  This  kind  of 
manufactory  is  out  of  place  in  towns,  because  buying  beets 
is  much  more  expensive  than  raising  them,  the  mash  can- 
not be  rendered  productive,  labor  and  fuel  are  more  expen- 
sive, and  there  is  not,  as  upon  a  farm,  a  supply  of  labor 
both  of  men  and  animals. 

But  can  this  manufacture  be  reconciled  with  the  interests 
of  our  colonies  ? 

Before  the  revolution,  this  would  have  been  a  difficult 
question  to  answer.  Then,  our  colonies  not  only  supplied 
our  own  wants,  but  furnished  an  overplus  worth  about 
80,000,000,  which  we  exported  to  foreign  countries,  partic- 
ularly to  those  of  the  north  of  Europe.  From  these  we 
received  in  exchange  timber,  iron,  copper,  hemp,  tallow, 
tar,  &.C.  The  loss  of  our  principal  colonies  has  caused  this 
important  trade  to  pass  into  other  hands,  and  those  colonies 
that  remain  to  us  do  not  furnish  sugar  enough  for  the  con- 
sumption of  our  own  country. 

The  government  has,  at  this  time,  two  ends  to  attain, 
one  of  which  is,  the  advancing  of  the  welfare  of  our  colo- 
nies, and  the  other,  the  encouragement  of  the  manufacture 
of  beet  sugar.  Both  would  be  accomplished  by  prohibiting 
the  importation  of  foreign  sugars.  When  this  is  done,  the 
sugar  of  our  colonies  will  find  an  advantageous  market, 
and  the  manufactories  of  beet  sugar  will  increase  in  num- 
ber. 

Supposing  the  wants  of  France  should  be  supplied  by 
the  sugar  from  beets,  —  could  we  not  then  resume  our  com- 
merce with  foreign  nations,  by  means  of  our  colonial  sugar  ? 
France  would,  at  the  same  time,  be  safe  from  the  danger  of 
privation,  and  from  those  variations  in  price  which  are  pro- 
duced by  a  maritime  war. 


356  CHYMISTRY    APPLIED    TO    AGRICULTURE. 

It  is  a  fact  that  if  the  government  do  not  interest  itself 
seriously  in  this  important  subject,  neither  the  colonies  nor 
the  manufactories  will  ever  acquire  a  great  degree  of  pros- 
perity ;  and  one  of  the  finest  discoveries  of  modern  times 
will  be  lost  to  France. 


INDEX 


Acid,  carbonic,  (oas,)  one  of  the  fluids  contained  in  the  atmosphere  , 
its  proportion  to  azote  and  oxygen,!.  —  Its  absorption  by  the  leaves 
of  plants,  2,  5.  —  Its  combination  with  lime,  5,  32.  —  Its  solution  in 
liquids,  5.  —  Produced  by  germination,  77,78.  — Its  influence  upon 
the  nutrition  of  vegetables,  80.  —  Its  decomposition,  81.  —  Furnished 
by  ripe  fruits,  87,  88.  —  By  leaves,  fruits,  and  roots,  132. 

Acids,  vegetable,  their  differences  at  difierent  periods  of  vegetation ; 
those  most  abundant,  159.  —  Processes  for  extracting  them,  162  et 
seq.  —  Their  uses  and  properties,  ibid. 

Affinities,  laws  which  affect  bodies,  3  et  seq. 

Agriculture,  its  importance,  xi.  —  Its  progress,  xii.  —  Its  wants,  xiii. 
—Conditions  necessary  to  hasten  its  progress,  xxi.  —  Interests  and 
duties  of  government,  ibid.  —  Foreign  products  which  it  may  yet  ap- 
propriate ;  table  of  the  products  of  French  agriculture,  131. 

Air,  its  action  upon  vegetation,  upon  different  soils ;  what  it  supplies 
to  the  plant  J  its  action  upon  dead  vegetables,  upon  fruits,  21-41, 

Albumen,  its  existence  in  many  vegetables,  154.  —  Its  uses,  its  analy- 
sis, 154,  155. 

Alcohol,  a  means  of  preserving  animal  substances  from  putrefaction, 
202, 270.  —  Of  hydrometers,  269.  —  Alcohol  from  cider,  270.  —  From 
wild  cherries,  ibid.  —  From  molasses,  ibid. 

Alkalies,  fixed,  168. 

Alumina,  enters  into  the  composition  of  arable  soils,  18.  — Is  abundant 
in  clays,  27.  —  Process  for  obtaining  it  pure,  31.  —  Its  specific  gravi- 
ty, ibid.  —  Its  properties  and  composition,  ibid.  —  Its  action  upon 
water,  35,  —  It  combines  with  oils,  39. 

Ammonia,  62. 

Animals,  number  of  animals  employed  in  French  agriculture,  132. 

Ashes,  of  mould,  17.  — Action  of  the  ashes  of  turf  and  pit  coal  as  ma- 
nures, 76.  —  Effects  of  the  ashes  from  our  domestic  fires,  76,  77.  — 
The  ashes  obtained  from  different  vegetables,  table  of  experiments 
made,  170. 


358 


INDEX. 


Azote,  one  of  the  fluids  composing  the  atmosphere,  1,7. —  Its  propor- 
tion, influence,  and  properties,  2.  —  Its  specific  gravity,  ibid.  —  Its 
influence  upon  vegetation,  92. 


B. 

Beer,  a  refreshing  drink,  279. 

Beet,  its  cultivation,  315.  —  Choice  of  seeds,  316.  —  Choice  of  a  soil, 
317.  —  Preparation  of  the  soil,  318.  —Method  of  sowing,  319.  —  Care 
during  vegetation,  320.  —  Pulling,  321.  —  Preservation,  322.—  Ex- 
traction of  the  sugar,  324.  —  Picking,  ibid.  —  Rasping,  325.  —  Extrac- 
tion of  the  juice,  ibid.  —  Clarification,  327.  —  Concentration,  evapora- 
tion, 330.  —  Boiling  of  the  sirups,  331.  —  Boiling  of  the  molasses  and 
leaching  sirups, 336.—  Refining,  337.  —  Clarification, 338.  —  Bleach- 
ing, 339.  —  Distillation  of  the  molasses,  345.  —  Product  of  a  sugar- 
house,  347, 348.  —  Product  in  sugar,  348.  —Additional  products, 348, 
349.  —  Table  of  products,  350.  —  Expenses,  351.  —  General  consid- 
erations, 354. 

Bones,  an  active  means  of  fertihzing  lands,  58.  —  Their  composition, 
reduction  to  powder,  uses,  59.  —  Advantages  afforded  by  them,  76. 

Buildings,  in  the  country,  means  of  rendering  them  healthy,  283. — 
Necessary  conditions,  284.  —  Choice  of  a  situation,  284,285.  —  Pre- 
cautions to  be  observed,  285.  —  Purification  of  stables  and  sheepfolds, 
286  et  seq. 

Burning,  of  a  soil,  114.  —  Its  utility,  and  inconveniences,  115. 

Butter,  one  of  the  elements  of  milk,  208.  —  Mode  of  obtaining  it,  210. 
—  Its  color,  ibid.  —  Its  becoming  rancid,  213.  —  Means  of  preserv- 
ing it,  ibid. 


Caloric,  one  of  the  fluids  existing  in  all  bodies,  1. 

Calou,  a  drink,  279, 

Canals,  advantages  of  them,  xxv,  237. 

Carbon,  17.  —  Its  combination  with  oxygen,  87.  —  Supplied  by  leaves, 
fruits,  and  roots,  133. 

Carbonate,  state  of  lime  in  soils  devoted  to  cultivation,  32.  —  Carbo- 
nates of  lime  and  magnesia,  47  et  seq. 

Carbonic  acid.     See  Acid. 

Chalk,  preserves  animal  and  vegetable  substances  from  too  rapid  a 
decomposition,  39.  —  Suitable  to  argillaceous  soils,  ibid. 

Cheese,  208,  221. 

Chica,  a  drink,  279. 

Chlorine,  utility  of  fumigations  with  it,  in  purifying  dwellings,  288. 

Chymistry,  its  progress,  xiv,  xvii.  —  Limits  which  it  has  not  yet  been 
able  to  pass,  xviii}  ziz. — Its  application  to  agriculture,  xix,  xz. 


INDEX.  359 

Clays,   their  nature,   27.  —  Unproductive,   whatever  may  be  the 

cause,  28. 
Clearing  of  lands,  xxiii. 
Composts,  how  formed,  64,  65. 
Cream,  its  nature,  preservation,  uses,  208,  209. 
Crises,  manufacturing  and  commercial, less  numerous  in  France  than 

in  England,  223. 
Cropping,  explained,  120,  121.  —  Principles  which  should  guide  the 

agriculturist,  121, 124.  —  Examples  of  cropping  upon  compact  soils, 

130.  —  Upon  light  soils,  ibid.  —  Upon  siliceous  soils,  ibid.  —  Upon 

soils  suitable  for  wheat,  131. 


D. 

Dews,  more  abundant  in  the  south  than  in  the  north,  33.  —  Their  ef- 
fects, ibid. 

Distillation,  252.  —  Processes  of  the  ancients,  252,  253.  —  Its  prog- 
ress, 254.  —  Different  methods,  ibid.  —  New  processes,  259-262.  — 
Variety  of  apparatus  for  distilling,  263. 

Division  of  landed  estates,  xxx.  —  Division  of  the  soil  into  small  es- 
tates, 226  et  seq. 

Domains  to  be  devoted  to  agricultural  instruction,  233.  —  Various 
qualities  which  the  soil  should  possess,  ibid. 

Drinks,  for  the  use  of  common  people ;  means  of  rendering  them 
healthy,  271  et  seq.  —  Fermented,  273.  —  Method  of  preparing  them, 
274.  —  Vinous,  c&Wed piquettes,  275,  —  Their  utility,  276.  —  Obtained 
from  the  sap  of  trees,  279.  —  Mode  of  making  caZow,  at  Cor omandel, 
ibid.  —  Of  making  chica,  in  America,  ibid.  —  Of  making  quass,  in 
Russia,  280. 

Drying,  employed  as  a  means  of  preservation,  183.  — Processes,  184 
et  seq. 

Dung,  its  properties,  64.  —  Salts  which  it  contains,  ibid.  —  Adaptation 
of  it  to  each  variety  of  soil,  ibid.  —  Fowls',  61.  —  Night-soil,  ibid.  — 
Lands  and  plants  to  which  it  is  suited,  ibid.  —  Perfection  of  this 
branch  of  business  in  Belgium,  62. 


£arths,  their  nature,  action  upon  vegetation,  14.  —  Principles  to  which 
they  owe  their  fertility,  17, 18.  —  Formed  by  the  waste  of  mountains, 
19,20.  —  Origin  of  the  earths  which  cover  the  table-lands  of  moun- 
tains, 21.  —  Actual  composition  of  arable  soils, .19.  —  Those  earths 
which  can  pass  into  plants,  26,  27.  —  Their  properties,  30.  —  Those 
best  suited  to  absorb  moisture,  35.  —  Analysis  of  them,  44.  —  Their 
desiccation  by  fire,  45.  —  Dissolved  by  acids,  46.  —  Of  earths,  salts, 


Z60 


INDEX. 


animal  and  vegetable  substances,  46,  47.  —  Magnesian  earths,  not 
very  fertile,  72,  73. 

Electricity,  an  imponderable  fluid,  8  et  seq. — Its  influence  upon 
vegetation,  ibid. 

Encouragement  which  the  government  ought  to  grant  to  French 
.  agriculture,  232.  —  Useful  associations,  ibid. 

Estates,  if  the  division  of  them  be  beneficial  or  injurious,  197. — 
Where  it  should  stop,  225.  —  Of  large  and  small  estates,  224.  —  Ad- 
vantages resulting  from  the  liberty  of  acquiring  landed  property,  ibid. 

Exchanges,  xxv. 

F. 

Fallow  lands,  causes  which  have  perpetuated  thera,  117.  —  Preju- 
dicial to  the  interests  of  agriculture,  117, 118. 

Fermentation,  general  views,  238,  239. —  Alcoholic,  239.  —  Of 
leaven,  ferment,  or  yeast,  240.  —  Of  the  must  of  the  grape,  241.  — 
Improvement  in  the  processes  for  making  wine,  243, 244.  —  Fermen- 
tation of  grains,  248.  —  Of  potatoes,  248,  249.  —  Of  the  mash  of 
grapes,  275.  —  Of  apples  and  pears,  276.  —  Of  cherries  and  mazzards, 
277.  —  Of  the  berries  of  the  service-tree,  278.  —  Of  plums  and  figs, 
ibid.  —  Of  juniper  berries,  iAid.  —  Of  the  sap  of  trees,  279.  —  Of 
barley  and  rye,  ibid,  et  seq. 

Fibre,  vegetable,  analysis  of  it,  149.  —  Use  made  of  it  in  manufac- 
tures, 150.  —  Methods  of  reducing  it  to  charcoal,  152  et  seq.  — Uses 
of  charcoal,  153, 154. 

Filtration  of  water,  273. 

Flax,  the  soaking  of  it  in  water,  150.  —  Opinions  respecting  the  ma- 
chines substituted  for  the  action  of  water,  ibid. 

Flints,  or  pebbles,  eifect  of  mixing  thenx  with  arable  soils,  40. 

Fluids,  contained  in  the  atmosphere,  2,  8,  et  seq. 

Forests,  means  of  encouraging  the  planting  and  preservation  of 
them,  xxiv. 

Fructification,  95,  96. 

Fruits,  86.  —  Ripening  of  them,  87.  —  Mode  of  preserving  themfibid. 
—  When  ripe,  yield  carbonic  acid,  87,  88. 

G. 

Gas,  carbonic  acid.     See  Acid.  —  Azote  and  oxygen,  1,  2. 

Gelatine,  its  decomposition  in  earth,  its  solution  in  water,  59. — 
Abounds  in  the  horns  and  hoofs  of  animals,  60. 

Germination,  77. 

Gluten,  a  vegeto-animal  principle,  154,  155.  —  Its  existence  and  pro- 
portions in  wheat,  156.  —  Its  influence  upon  clarification,  159. 


INDEX.  361 

Grains,  means  of  preserving  them,  190.    See  Trenches. 

Gravel,  its  presence  necessary  in  a  good  soil,  26. —  Utility  of  mixing 

it  with  impoverished  soils,  26,  27. 
Gums,  their  nature,  135.  — Their  use  in  the  arts,  135.  —  Employed  as 

food,  ibid,  —  Analysis  of  them,  136. 

H. 

Heat,  its  effect,  xv.  —  Its  influence  upon  bodies,  9.  —  Unequal  propor- 
tion of  this  fluid  in  bodies,  ibid.  —  Phenomena  produced  by  its  emis' 
sion  and  absorption,  ibid.  —  Its  effects,  dilation,  fluidity,  motion,  11. 
—  Combustion  of  vegetables  in  large  masses,  15.  —  Its  action  upon 
the  plant,  36.  —  Upon  animals,  ibid.  —  Different  upon  different  soils, 
ibid.  —  Developed  more  or  less  by  manures,  37.  —  Its  influence  upon 
germination,  77.  —  Upon  vegetation,  58  et  seg. 

Horns,  their  effects  as  a  manure,  60.  — The  advantages  of  employing 
them,  76. 

Hydrogen  (gas),  15. 

Hydrometer,  269. 

I. 

Implements  of  HosBANDRY,comparison  of  tillage  performed  with  the 
hoe,  spade,  and  plough,  107.  —  Use  of  the  harrow  and  roller,  108,109. 

Indigo.     See  Woad. 

Instruction,  special,  in  agriculture ;  its  necessity  and  utility,233  etseq. 

Irrigation,  its  use  according  to  the  nature  of  soils,  116.  —  Times  most 
favorable  to  it,  117. 

L. 

Lamp-black,  149. 

Laws  called  for  by  agriculture,  xviii  et  aeq. 

Leases,  inconveniences  resulting  frcHu  their  sj^prt  duration,  xxjciv. 

Leather,  158. 

Leaves,  principal  organs  of  nutrition,  35  et  seq. 

Ley-washing,  cleansing  of  fabrics  of  hemp,  &c.,  289.  —  An  economical 
liquor  for  supplying  the  place  of  soap  ;  mode  of  using  it,  290.  —  Ap- 
paratus for  whitening  household  linen,  290.  —  Processes  for  whiten- 
ing cotton  thread,  290. 

Life,  agricultural,  preferable  to  a  manufnetarmg  life,  223. 

Light,  one  of  the  fluids  diffused  through  the  atmosphere,  1.--^  Its  influ- 
ence upon  vegetation, 12, 13.  —  Upon  germination,  79. —  Upon  nirtri- 
tion,  81.  —  Necessary  to  the  giving  out  of  oxygen  gas  by  leaves,  101. 

Lime,  enters  into  the  composition  of  arable  soils,  18.  —  Deprives  theui^ 
of  its  carbonic  acid,  21. —  Process  for  obtaining  it  pure ;  its  properties, 
31 


3^  INDEX. 

32.  —  Absorbs  water,  ibid.  —  What  limestone  loses  by  calcination,  68, 
69. — Air-slacked ;  its  uses  in  agriculture,  69. — Danger  of  using  quick- 
\naie,ihid.  — Its  combination  with  vegetable  and  animal  substances,69, 
70.  —  Its  action  upon  lands,  71.  —  Mode  of  employing  and  preparing 
it,  ibid.  —  Presence  and  effects  of  magnesia  in  calcareous  roeks,  72. 
—  Use  of  lime  for  the  purification  of  sheep-folds,  86,  87. 

Liquors,  alcoholic,  method  of  making  them,  201,  202. 

Litharge,  145.  • 

M. 

Magnesia,  sometimes  enters  into  the  composition  of  arable  soils,  18. 
Manures,  XXX,  49.  —  Their  nature  and  action,  49, 50, 66.  —  DilSerence 

between  nutritive  and  stimulating  manures,  75,  76. 
Manuring,  the  process,  106.  — Its  effects,  107.  —  Varied  according  to 

the  nature  of  the  soil,  109. 
Marl,  its  composition,  28.  —  Its  properties,  qualities,  mixtures  with 

other  substances,  29. 
Milk,  207.  —  Principles  which  it  contains,  and  modes  of  separating 

them,  211.  —  Goats'  milk, ibid.  — Woman's  milk,  ibid.  —  Asses'  milk, 

212.  —  Mares'  milk,  ibid,  et  seq. 
Mixture  of  earths,  26,  27.  —  Their  properties,  38. —  Of  chalk,  silex, 

alumina,  38,  39. 
Mould,  its  formation,  15. — Principles  which  it  contains,  ibid. — Product 

of  its  distillation  in  a  retort,  16.  —  Its  decomposition,  17.  —  Its  ef- 
fects upon  vegetation,  36,  81. 
Mountains,  their  decomposition  causes  the  formation  of  arable  lands, 

19-23. 


N. 

Nations,  agricultural  and  manufacturing;  difference  between  them,221. 
Nutrition  of  Plants,  its  operation,  80  et  seq. — Summary  of  the 
phenomena  attending  it,  99  et  seq. 


Oils,  their  character ;  fixed  and  volatile,  142, 143.  —  Mode  of  extracting 
them,  143, 144.  —  Processes  for  purifying  them,  ibid.  —  Fixed  oils 
combined  with  metallic  oxides,  144, 145.  —  Their  uses,  145.  —  Vola- 
tile oils,  146.  —  Plants  which  furnish  them,  146,  147.  —Their  uses, 
ibid. 

Oxygen  (gas),  forms  one  fifth  part  of  the  atmosphere,  2  et  seq.  —  One 
of  the  elements  of  vegetable  productions ;  principal  agent  of  germina- 


INDEX. 


363 


tion,  77,  78,  —  Plants  which  absorb  the  largest  proportion  of  it,  83, 
84.  —  Its  action  upon  fruits,  85. 


Plaster,  employment  of  it  as  a  manure,  72, 73. —  Its  composition,  73. 

—  Use  of  crude  and  baked  plaster  compared,  74.  —  Its  effects,  ibid. 

—  To  what  its  action  is  to  be  attributed,  ibid,  et  seq.  —  Its  solubility 
in  water,  75.  —  Its  influence  upon  the  quality  of  salts,  69. 

Potash,  how  extracted;  its  use,  168,  171,  172. —  Table  of  the  re- 
sults obtained  by  its  extraction  from  differejit  vegetables,  171.  —  Its 
analysis,  173  et  seq. 

PouDRETTK,  its  good  effccts  as  a  manure,  63. 

Preservation,  causes  which  affect  the  deterioration  of  animal  and 
vegetable  substances,  182.  —  Means  of  preserving  them,  183. 

Prizes,  should  be  offered  for  the  encouragement  and  furtherance  of 
agricultural  science,  234  et  seq. 

QuAss,  a  drink,  280- 


Resins,  147.  —  Sap  of  trees,  ibid.  —  Means  of  obtaining  them,  148.  — 
Their  uses,  148, 149. 

Roads,  district,  necessity  of  a  law  relating  to  them,  xxiv. 

Roots,  one  of  the  organs  of  nutrition  of  plants,  80.  —  Juices  and  salts 
which  they  draw  from  the  earth,  ibid.  —  Portion  of  oxygen  which 
they  absorb,  84,  —  Absorb  the  oxygen  which  exists  in  water,  84, 85. 

S. 

Salting,  a  means  of  preserving  meats,  202.  —  Different  methods,  203, 
204.  —  Salting  of  butter,  206. 

Salts,  their  influence  upon  vegetation,  41.  —  Their  chymical  action, 
ibid.  —  Means  of  knowing  the  quantity  of  them  in  soils,  48.  —  Prop- 
erties and  characteristics  of  nitre,  of  marine  salt,  of  sulphate  of  soda, 
48, 49.  —  Absorption  of  them  by  plants,  66, 68.  —  Abundant  in  herba- 
ceous plants,  98,  99. — Suitable  to  argillaceous  soils,  110.  —  Those 
most  common  in  vegetables,  175.  —  Those  most  proper  for  salting, 
202.  ^-  Disastrous  tax  on  salt,  xxviii. 

Sap,  influence  of  temperature  upon  it,  104, 105.  —  Its  elaboration  in 
vegetables,  134.  —  Use  made  of  it  in  various  countries  for  making 
drinks,  279. 

Shxepfolds,  286. 


364  INDEX. 

Silica,  enters  into  the  composition  of  arable  soils,  18.  —  Its  mixture 
with  aiumina., ibid.  —  Process  for  obtaining  it  pure,  30.  —  Abundant 
in  vegetables,  31.  — Properties,  35. 

Sirups,  processes  for  making  them,  187. 

Soda,  extraction  of  it  from  marine  plants,  173. 

Soils,  their  nature,  their  elements,  18,  19,23,24,  25.  —  Mixtures  of 
them,  27,  28.  —  Their  fertility,  as  affected  by  their  composition  and 
exposure,  40,  41.  —  Exhausted  by  long  cultivation,  110. 

Stables  and  Sheepfolds,  purification  of  the  air  in,  286. 

Starch  or  Fecula,  136.  —  Its  use,  136,  137.  —  Process  for  obtaining 
it,  137  et  seq. 

Straw,  a  weak  manure,  63. 

Sugar,  to  what  the  name  is  applied,  140.  —  Three  kinds  known,  ibid. 
—  Vegetables  which  yield  them,  140, 141.  —  Their  specific  gravity, 
141.  —  Extraction  of  sugar  from  beets.     See  Beet. 

Sulphur,  fumigation  with  it  for  purifying  sheepfolds,  286. 

Sweat,  animal,  61.  —  Its  analysis,  ibid. 

T. 

Tannin,  its  characteristics,  proper  uses,  and  the  mode  of  extracting  it, 
158.  —  Improvement  of  the  art  of  the  tanner,  158.  —  Combination 
of  tannin  with  gelatine,  203. 

Tar,  how  obtained,  148.  —  Process  for  improving  it,  ibid. 

Tax,  upon  salt,  a  public  calamity,  xxvii. 

Temperature,  its  variations  and  effects,  11, 12. 

Tillage,  its  advantages,  varieties,  appropriate  periods,  depth,  accord- 
ing to  the  nature  of  soils  and  plants,  42.  —  Soils  which  require  more 
or  less  tillage,  107, 108  et  seq. 

Trees,  resinous,  147,  148. 

Trenches,  suited  to  the  preservation  of  grains,  190, 194. 

U. 

Urine,  as  a  manure,  57.  —  Varieties  in  the  urine  of  animals,  ibid — 
Its  efficiency  in  composts,  58.  —  Its  combination  with  plaster  and 
lime,  ibid. 

V. 

Vapors,  aqueous,  their  effects,  32,  33. 
Vegetable  acids.     See  Acids. 
Vitality,  its  laws,  xviii. 


INDEX.  365 


w. 


Water,  one  of  the  fluids  diffused  through  the  atmosphere,  1.  —  Its  va- 
riations and  effects,  as  modified  by  temperature,  7.  —  Its  passage  into 
the  state  of  ice,  21.  —  Its  action  upon  vegetables,  33.  —  Its  absorp- 
tion by  soils,  34. —  Concurs  in  germination,  77,  78.  —  Its  influence 
upon  the  nutrition  of  plants,  89.  —  Properties  of  different  waters, 
89,  90,  91.  —  Serves  as  a  vehicle  to  the  air,  92.  —  Hastens  the  fer- 
mentation of  manures,  116.  —  Its  different  states  in  the  plant,  201. 

—  Different  qualities  of  well-water,  271 .  —  Cistern- water,  272.  — 
Water  of  pools,  ibid.  —  Filtration  of  water,  273. 

Wax,  exists  in  some  plants,  141.  —  Its  extraction,  ifti<Z.  —  Its  use  in 
the  arts,  ibid. 

WoAD,  294,  295.  —  Extraction  of  indigo  from  woad  ;  variation  in  the 
coloring  principle,  297.  —  Gathering  of  the  leaves,  298.  —  Manufac- 
ture of  the  cakes,  300  et  seq.  —  Refining,  ibid.  —  Dying  of  stuffs, 
301.  —  Means  of  improving  the  process  of  extracting  the  indigo,  303. 

—  Establishments  at  Albi,  303. —  Difference  in  the  indigoes obtained, 
304.  —  Process,  ibid,  et  seq.  —  Of  beating,  307.  —  Of  precipitation, 
Hid.  —  Of  washing,  309.  —  Drying,  311.  —  Sweating,  ibid.  —  Esti- 
mates of  the  product,  312  et  seq.  —  Encouragement  desirable,  314. 

Wool,  refuse,  employed  as  a  manure,  GO  et  seq. 
Workshops,  which  should  be  united  to  an  establishment  for  special 
instruction,  232. 


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